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1/*
2 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
3 *
4 * Copyright (c) 2010 Red Hat Inc.
5 * Author : Dave Airlie <airlied@redhat.com>
6 *
7 * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the next
17 * paragraph) shall be included in all copies or substantial portions of the
18 * Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 * DEALINGS
27 * IN THE SOFTWARE.
28 *
29 */
30
31#define pr_fmt(fmt) "vga_switcheroo: " fmt
32
33#include <linux/console.h>
34#include <linux/debugfs.h>
35#include <linux/fb.h>
36#include <linux/fs.h>
37#include <linux/module.h>
38#include <linux/pci.h>
39#include <linux/pm_domain.h>
40#include <linux/pm_runtime.h>
41#include <linux/seq_file.h>
42#include <linux/uaccess.h>
43#include <linux/vgaarb.h>
44#include <linux/vga_switcheroo.h>
45
46/**
47 * DOC: Overview
48 *
49 * vga_switcheroo is the Linux subsystem for laptop hybrid graphics.
50 * These come in two flavors:
51 *
52 * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs.
53 * * muxless: Dual GPUs but only one of them is connected to outputs.
54 * The other one is merely used to offload rendering, its results
55 * are copied over PCIe into the framebuffer. On Linux this is
56 * supported with DRI PRIME.
57 *
58 * Hybrid graphics started to appear in the late Naughties and were initially
59 * all muxed. Newer laptops moved to a muxless architecture for cost reasons.
60 * A notable exception is the MacBook Pro which continues to use a mux.
61 * Muxes come with varying capabilities: Some switch only the panel, others
62 * can also switch external displays. Some switch all display pins at once
63 * while others can switch just the DDC lines. (To allow EDID probing
64 * for the inactive GPU.) Also, muxes are often used to cut power to the
65 * discrete GPU while it is not used.
66 *
67 * DRM drivers register GPUs with vga_switcheroo, these are henceforth called
68 * clients. The mux is called the handler. Muxless machines also register a
69 * handler to control the power state of the discrete GPU, its ->switchto
70 * callback is a no-op for obvious reasons. The discrete GPU is often equipped
71 * with an HDA controller for the HDMI/DP audio signal, this will also
72 * register as a client so that vga_switcheroo can take care of the correct
73 * suspend/resume order when changing the discrete GPU's power state. In total
74 * there can thus be up to three clients: Two vga clients (GPUs) and one audio
75 * client (on the discrete GPU). The code is mostly prepared to support
76 * machines with more than two GPUs should they become available.
77 *
78 * The GPU to which the outputs are currently switched is called the
79 * active client in vga_switcheroo parlance. The GPU not in use is the
80 * inactive client. When the inactive client's DRM driver is loaded,
81 * it will be unable to probe the panel's EDID and hence depends on
82 * VBIOS to provide its display modes. If the VBIOS modes are bogus or
83 * if there is no VBIOS at all (which is common on the MacBook Pro),
84 * a client may alternatively request that the DDC lines are temporarily
85 * switched to it, provided that the handler supports this. Switching
86 * only the DDC lines and not the entire output avoids unnecessary
87 * flickering.
88 */
89
90/**
91 * struct vga_switcheroo_client - registered client
92 * @pdev: client pci device
93 * @fb_info: framebuffer to which console is remapped on switching
94 * @pwr_state: current power state
95 * @ops: client callbacks
96 * @id: client identifier. Determining the id requires the handler,
97 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
98 * and later given their true id in vga_switcheroo_enable()
99 * @active: whether the outputs are currently switched to this client
100 * @driver_power_control: whether power state is controlled by the driver's
101 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
102 * interface is a no-op so as not to interfere with runtime pm
103 * @list: client list
104 *
105 * Registered client. A client can be either a GPU or an audio device on a GPU.
106 * For audio clients, the @fb_info, @active and @driver_power_control members
107 * are bogus.
108 */
109struct vga_switcheroo_client {
110 struct pci_dev *pdev;
111 struct fb_info *fb_info;
112 enum vga_switcheroo_state pwr_state;
113 const struct vga_switcheroo_client_ops *ops;
114 enum vga_switcheroo_client_id id;
115 bool active;
116 bool driver_power_control;
117 struct list_head list;
118};
119
120/*
121 * protects access to struct vgasr_priv
122 */
123static DEFINE_MUTEX(vgasr_mutex);
124
125/**
126 * struct vgasr_priv - vga_switcheroo private data
127 * @active: whether vga_switcheroo is enabled.
128 * Prerequisite is the registration of two GPUs and a handler
129 * @delayed_switch_active: whether a delayed switch is pending
130 * @delayed_client_id: client to which a delayed switch is pending
131 * @debugfs_root: directory for vga_switcheroo debugfs interface
132 * @switch_file: file for vga_switcheroo debugfs interface
133 * @registered_clients: number of registered GPUs
134 * (counting only vga clients, not audio clients)
135 * @clients: list of registered clients
136 * @handler: registered handler
137 * @handler_flags: flags of registered handler
138 * @mux_hw_lock: protects mux state
139 * (in particular while DDC lines are temporarily switched)
140 * @old_ddc_owner: client to which DDC lines will be switched back on unlock
141 *
142 * vga_switcheroo private data. Currently only one vga_switcheroo instance
143 * per system is supported.
144 */
145struct vgasr_priv {
146 bool active;
147 bool delayed_switch_active;
148 enum vga_switcheroo_client_id delayed_client_id;
149
150 struct dentry *debugfs_root;
151 struct dentry *switch_file;
152
153 int registered_clients;
154 struct list_head clients;
155
156 const struct vga_switcheroo_handler *handler;
157 enum vga_switcheroo_handler_flags_t handler_flags;
158 struct mutex mux_hw_lock;
159 int old_ddc_owner;
160};
161
162#define ID_BIT_AUDIO 0x100
163#define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
164#define client_is_vga(c) ((c)->id == VGA_SWITCHEROO_UNKNOWN_ID || \
165 !client_is_audio(c))
166#define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
167
168static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
169static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
170
171/* only one switcheroo per system */
172static struct vgasr_priv vgasr_priv = {
173 .clients = LIST_HEAD_INIT(vgasr_priv.clients),
174 .mux_hw_lock = __MUTEX_INITIALIZER(vgasr_priv.mux_hw_lock),
175};
176
177static bool vga_switcheroo_ready(void)
178{
179 /* we're ready if we get two clients + handler */
180 return !vgasr_priv.active &&
181 vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
182}
183
184static void vga_switcheroo_enable(void)
185{
186 int ret;
187 struct vga_switcheroo_client *client;
188
189 /* call the handler to init */
190 if (vgasr_priv.handler->init)
191 vgasr_priv.handler->init();
192
193 list_for_each_entry(client, &vgasr_priv.clients, list) {
194 if (client->id != VGA_SWITCHEROO_UNKNOWN_ID)
195 continue;
196 ret = vgasr_priv.handler->get_client_id(client->pdev);
197 if (ret < 0)
198 return;
199
200 client->id = ret;
201 }
202 vga_switcheroo_debugfs_init(&vgasr_priv);
203 vgasr_priv.active = true;
204}
205
206/**
207 * vga_switcheroo_register_handler() - register handler
208 * @handler: handler callbacks
209 * @handler_flags: handler flags
210 *
211 * Register handler. Enable vga_switcheroo if two vga clients have already
212 * registered.
213 *
214 * Return: 0 on success, -EINVAL if a handler was already registered.
215 */
216int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
217 enum vga_switcheroo_handler_flags_t handler_flags)
218{
219 mutex_lock(&vgasr_mutex);
220 if (vgasr_priv.handler) {
221 mutex_unlock(&vgasr_mutex);
222 return -EINVAL;
223 }
224
225 vgasr_priv.handler = handler;
226 vgasr_priv.handler_flags = handler_flags;
227 if (vga_switcheroo_ready()) {
228 pr_info("enabled\n");
229 vga_switcheroo_enable();
230 }
231 mutex_unlock(&vgasr_mutex);
232 return 0;
233}
234EXPORT_SYMBOL(vga_switcheroo_register_handler);
235
236/**
237 * vga_switcheroo_unregister_handler() - unregister handler
238 *
239 * Unregister handler. Disable vga_switcheroo.
240 */
241void vga_switcheroo_unregister_handler(void)
242{
243 mutex_lock(&vgasr_mutex);
244 mutex_lock(&vgasr_priv.mux_hw_lock);
245 vgasr_priv.handler_flags = 0;
246 vgasr_priv.handler = NULL;
247 if (vgasr_priv.active) {
248 pr_info("disabled\n");
249 vga_switcheroo_debugfs_fini(&vgasr_priv);
250 vgasr_priv.active = false;
251 }
252 mutex_unlock(&vgasr_priv.mux_hw_lock);
253 mutex_unlock(&vgasr_mutex);
254}
255EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
256
257/**
258 * vga_switcheroo_handler_flags() - obtain handler flags
259 *
260 * Helper for clients to obtain the handler flags bitmask.
261 *
262 * Return: Handler flags. A value of 0 means that no handler is registered
263 * or that the handler has no special capabilities.
264 */
265enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void)
266{
267 return vgasr_priv.handler_flags;
268}
269EXPORT_SYMBOL(vga_switcheroo_handler_flags);
270
271static int register_client(struct pci_dev *pdev,
272 const struct vga_switcheroo_client_ops *ops,
273 enum vga_switcheroo_client_id id, bool active,
274 bool driver_power_control)
275{
276 struct vga_switcheroo_client *client;
277
278 client = kzalloc(sizeof(*client), GFP_KERNEL);
279 if (!client)
280 return -ENOMEM;
281
282 client->pwr_state = VGA_SWITCHEROO_ON;
283 client->pdev = pdev;
284 client->ops = ops;
285 client->id = id;
286 client->active = active;
287 client->driver_power_control = driver_power_control;
288
289 mutex_lock(&vgasr_mutex);
290 list_add_tail(&client->list, &vgasr_priv.clients);
291 if (client_is_vga(client))
292 vgasr_priv.registered_clients++;
293
294 if (vga_switcheroo_ready()) {
295 pr_info("enabled\n");
296 vga_switcheroo_enable();
297 }
298 mutex_unlock(&vgasr_mutex);
299 return 0;
300}
301
302/**
303 * vga_switcheroo_register_client - register vga client
304 * @pdev: client pci device
305 * @ops: client callbacks
306 * @driver_power_control: whether power state is controlled by the driver's
307 * runtime pm
308 *
309 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
310 * handler have already registered. The power state of the client is assumed
311 * to be ON.
312 *
313 * Return: 0 on success, -ENOMEM on memory allocation error.
314 */
315int vga_switcheroo_register_client(struct pci_dev *pdev,
316 const struct vga_switcheroo_client_ops *ops,
317 bool driver_power_control)
318{
319 return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID,
320 pdev == vga_default_device(),
321 driver_power_control);
322}
323EXPORT_SYMBOL(vga_switcheroo_register_client);
324
325/**
326 * vga_switcheroo_register_audio_client - register audio client
327 * @pdev: client pci device
328 * @ops: client callbacks
329 * @id: client identifier
330 *
331 * Register audio client (audio device on a GPU). The power state of the
332 * client is assumed to be ON.
333 *
334 * Return: 0 on success, -ENOMEM on memory allocation error.
335 */
336int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
337 const struct vga_switcheroo_client_ops *ops,
338 enum vga_switcheroo_client_id id)
339{
340 return register_client(pdev, ops, id | ID_BIT_AUDIO, false, false);
341}
342EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
343
344static struct vga_switcheroo_client *
345find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
346{
347 struct vga_switcheroo_client *client;
348
349 list_for_each_entry(client, head, list)
350 if (client->pdev == pdev)
351 return client;
352 return NULL;
353}
354
355static struct vga_switcheroo_client *
356find_client_from_id(struct list_head *head,
357 enum vga_switcheroo_client_id client_id)
358{
359 struct vga_switcheroo_client *client;
360
361 list_for_each_entry(client, head, list)
362 if (client->id == client_id)
363 return client;
364 return NULL;
365}
366
367static struct vga_switcheroo_client *
368find_active_client(struct list_head *head)
369{
370 struct vga_switcheroo_client *client;
371
372 list_for_each_entry(client, head, list)
373 if (client->active)
374 return client;
375 return NULL;
376}
377
378/**
379 * vga_switcheroo_get_client_state() - obtain power state of a given client
380 * @pdev: client pci device
381 *
382 * Obtain power state of a given client as seen from vga_switcheroo.
383 * The function is only called from hda_intel.c.
384 *
385 * Return: Power state.
386 */
387enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev)
388{
389 struct vga_switcheroo_client *client;
390 enum vga_switcheroo_state ret;
391
392 mutex_lock(&vgasr_mutex);
393 client = find_client_from_pci(&vgasr_priv.clients, pdev);
394 if (!client)
395 ret = VGA_SWITCHEROO_NOT_FOUND;
396 else
397 ret = client->pwr_state;
398 mutex_unlock(&vgasr_mutex);
399 return ret;
400}
401EXPORT_SYMBOL(vga_switcheroo_get_client_state);
402
403/**
404 * vga_switcheroo_unregister_client() - unregister client
405 * @pdev: client pci device
406 *
407 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
408 */
409void vga_switcheroo_unregister_client(struct pci_dev *pdev)
410{
411 struct vga_switcheroo_client *client;
412
413 mutex_lock(&vgasr_mutex);
414 client = find_client_from_pci(&vgasr_priv.clients, pdev);
415 if (client) {
416 if (client_is_vga(client))
417 vgasr_priv.registered_clients--;
418 list_del(&client->list);
419 kfree(client);
420 }
421 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
422 pr_info("disabled\n");
423 vga_switcheroo_debugfs_fini(&vgasr_priv);
424 vgasr_priv.active = false;
425 }
426 mutex_unlock(&vgasr_mutex);
427}
428EXPORT_SYMBOL(vga_switcheroo_unregister_client);
429
430/**
431 * vga_switcheroo_client_fb_set() - set framebuffer of a given client
432 * @pdev: client pci device
433 * @info: framebuffer
434 *
435 * Set framebuffer of a given client. The console will be remapped to this
436 * on switching.
437 */
438void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
439 struct fb_info *info)
440{
441 struct vga_switcheroo_client *client;
442
443 mutex_lock(&vgasr_mutex);
444 client = find_client_from_pci(&vgasr_priv.clients, pdev);
445 if (client)
446 client->fb_info = info;
447 mutex_unlock(&vgasr_mutex);
448}
449EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
450
451/**
452 * vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client
453 * @pdev: client pci device
454 *
455 * Temporarily switch DDC lines to the client identified by @pdev
456 * (but leave the outputs otherwise switched to where they are).
457 * This allows the inactive client to probe EDID. The DDC lines must
458 * afterwards be switched back by calling vga_switcheroo_unlock_ddc(),
459 * even if this function returns an error.
460 *
461 * Return: Previous DDC owner on success or a negative int on error.
462 * Specifically, %-ENODEV if no handler has registered or if the handler
463 * does not support switching the DDC lines. Also, a negative value
464 * returned by the handler is propagated back to the caller.
465 * The return value has merely an informational purpose for any caller
466 * which might be interested in it. It is acceptable to ignore the return
467 * value and simply rely on the result of the subsequent EDID probe,
468 * which will be %NULL if DDC switching failed.
469 */
470int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
471{
472 enum vga_switcheroo_client_id id;
473
474 mutex_lock(&vgasr_priv.mux_hw_lock);
475 if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) {
476 vgasr_priv.old_ddc_owner = -ENODEV;
477 return -ENODEV;
478 }
479
480 id = vgasr_priv.handler->get_client_id(pdev);
481 vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id);
482 return vgasr_priv.old_ddc_owner;
483}
484EXPORT_SYMBOL(vga_switcheroo_lock_ddc);
485
486/**
487 * vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner
488 * @pdev: client pci device
489 *
490 * Switch DDC lines back to the previous owner after calling
491 * vga_switcheroo_lock_ddc(). This must be called even if
492 * vga_switcheroo_lock_ddc() returned an error.
493 *
494 * Return: Previous DDC owner on success (i.e. the client identifier of @pdev)
495 * or a negative int on error.
496 * Specifically, %-ENODEV if no handler has registered or if the handler
497 * does not support switching the DDC lines. Also, a negative value
498 * returned by the handler is propagated back to the caller.
499 * Finally, invoking this function without calling vga_switcheroo_lock_ddc()
500 * first is not allowed and will result in %-EINVAL.
501 */
502int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
503{
504 enum vga_switcheroo_client_id id;
505 int ret = vgasr_priv.old_ddc_owner;
506
507 if (WARN_ON_ONCE(!mutex_is_locked(&vgasr_priv.mux_hw_lock)))
508 return -EINVAL;
509
510 if (vgasr_priv.old_ddc_owner >= 0) {
511 id = vgasr_priv.handler->get_client_id(pdev);
512 if (vgasr_priv.old_ddc_owner != id)
513 ret = vgasr_priv.handler->switch_ddc(
514 vgasr_priv.old_ddc_owner);
515 }
516 mutex_unlock(&vgasr_priv.mux_hw_lock);
517 return ret;
518}
519EXPORT_SYMBOL(vga_switcheroo_unlock_ddc);
520
521/**
522 * DOC: Manual switching and manual power control
523 *
524 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
525 * can be read to retrieve the current vga_switcheroo state and commands
526 * can be written to it to change the state. The file appears as soon as
527 * two GPU drivers and one handler have registered with vga_switcheroo.
528 * The following commands are understood:
529 *
530 * * OFF: Power off the device not in use.
531 * * ON: Power on the device not in use.
532 * * IGD: Switch to the integrated graphics device.
533 * Power on the integrated GPU if necessary, power off the discrete GPU.
534 * Prerequisite is that no user space processes (e.g. Xorg, alsactl)
535 * have opened device files of the GPUs or the audio client. If the
536 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
537 * and /dev/snd/controlC1 to identify processes blocking the switch.
538 * * DIS: Switch to the discrete graphics device.
539 * * DIGD: Delayed switch to the integrated graphics device.
540 * This will perform the switch once the last user space process has
541 * closed the device files of the GPUs and the audio client.
542 * * DDIS: Delayed switch to the discrete graphics device.
543 * * MIGD: Mux-only switch to the integrated graphics device.
544 * Does not remap console or change the power state of either gpu.
545 * If the integrated GPU is currently off, the screen will turn black.
546 * If it is on, the screen will show whatever happens to be in VRAM.
547 * Either way, the user has to blindly enter the command to switch back.
548 * * MDIS: Mux-only switch to the discrete graphics device.
549 *
550 * For GPUs whose power state is controlled by the driver's runtime pm,
551 * the ON and OFF commands are a no-op (see next section).
552 *
553 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
554 * should not be used.
555 */
556
557static int vga_switcheroo_show(struct seq_file *m, void *v)
558{
559 struct vga_switcheroo_client *client;
560 int i = 0;
561
562 mutex_lock(&vgasr_mutex);
563 list_for_each_entry(client, &vgasr_priv.clients, list) {
564 seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
565 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" :
566 "IGD",
567 client_is_vga(client) ? "" : "-Audio",
568 client->active ? '+' : ' ',
569 client->driver_power_control ? "Dyn" : "",
570 client->pwr_state ? "Pwr" : "Off",
571 pci_name(client->pdev));
572 i++;
573 }
574 mutex_unlock(&vgasr_mutex);
575 return 0;
576}
577
578static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
579{
580 return single_open(file, vga_switcheroo_show, NULL);
581}
582
583static int vga_switchon(struct vga_switcheroo_client *client)
584{
585 if (client->driver_power_control)
586 return 0;
587 if (vgasr_priv.handler->power_state)
588 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
589 /* call the driver callback to turn on device */
590 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
591 client->pwr_state = VGA_SWITCHEROO_ON;
592 return 0;
593}
594
595static int vga_switchoff(struct vga_switcheroo_client *client)
596{
597 if (client->driver_power_control)
598 return 0;
599 /* call the driver callback to turn off device */
600 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
601 if (vgasr_priv.handler->power_state)
602 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
603 client->pwr_state = VGA_SWITCHEROO_OFF;
604 return 0;
605}
606
607static void set_audio_state(enum vga_switcheroo_client_id id,
608 enum vga_switcheroo_state state)
609{
610 struct vga_switcheroo_client *client;
611
612 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
613 if (client && client->pwr_state != state) {
614 client->ops->set_gpu_state(client->pdev, state);
615 client->pwr_state = state;
616 }
617}
618
619/* stage one happens before delay */
620static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
621{
622 struct vga_switcheroo_client *active;
623
624 active = find_active_client(&vgasr_priv.clients);
625 if (!active)
626 return 0;
627
628 if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
629 vga_switchon(new_client);
630
631 vga_set_default_device(new_client->pdev);
632 return 0;
633}
634
635/* post delay */
636static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
637{
638 int ret;
639 struct vga_switcheroo_client *active;
640
641 active = find_active_client(&vgasr_priv.clients);
642 if (!active)
643 return 0;
644
645 active->active = false;
646
647 set_audio_state(active->id, VGA_SWITCHEROO_OFF);
648
649 if (new_client->fb_info) {
650 struct fb_event event;
651
652 console_lock();
653 event.info = new_client->fb_info;
654 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
655 console_unlock();
656 }
657
658 mutex_lock(&vgasr_priv.mux_hw_lock);
659 ret = vgasr_priv.handler->switchto(new_client->id);
660 mutex_unlock(&vgasr_priv.mux_hw_lock);
661 if (ret)
662 return ret;
663
664 if (new_client->ops->reprobe)
665 new_client->ops->reprobe(new_client->pdev);
666
667 if (active->pwr_state == VGA_SWITCHEROO_ON)
668 vga_switchoff(active);
669
670 set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
671
672 new_client->active = true;
673 return 0;
674}
675
676static bool check_can_switch(void)
677{
678 struct vga_switcheroo_client *client;
679
680 list_for_each_entry(client, &vgasr_priv.clients, list) {
681 if (!client->ops->can_switch(client->pdev)) {
682 pr_err("client %x refused switch\n", client->id);
683 return false;
684 }
685 }
686 return true;
687}
688
689static ssize_t
690vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
691 size_t cnt, loff_t *ppos)
692{
693 char usercmd[64];
694 int ret;
695 bool delay = false, can_switch;
696 bool just_mux = false;
697 enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID;
698 struct vga_switcheroo_client *client = NULL;
699
700 if (cnt > 63)
701 cnt = 63;
702
703 if (copy_from_user(usercmd, ubuf, cnt))
704 return -EFAULT;
705
706 mutex_lock(&vgasr_mutex);
707
708 if (!vgasr_priv.active) {
709 cnt = -EINVAL;
710 goto out;
711 }
712
713 /* pwr off the device not in use */
714 if (strncmp(usercmd, "OFF", 3) == 0) {
715 list_for_each_entry(client, &vgasr_priv.clients, list) {
716 if (client->active || client_is_audio(client))
717 continue;
718 if (client->driver_power_control)
719 continue;
720 set_audio_state(client->id, VGA_SWITCHEROO_OFF);
721 if (client->pwr_state == VGA_SWITCHEROO_ON)
722 vga_switchoff(client);
723 }
724 goto out;
725 }
726 /* pwr on the device not in use */
727 if (strncmp(usercmd, "ON", 2) == 0) {
728 list_for_each_entry(client, &vgasr_priv.clients, list) {
729 if (client->active || client_is_audio(client))
730 continue;
731 if (client->driver_power_control)
732 continue;
733 if (client->pwr_state == VGA_SWITCHEROO_OFF)
734 vga_switchon(client);
735 set_audio_state(client->id, VGA_SWITCHEROO_ON);
736 }
737 goto out;
738 }
739
740 /* request a delayed switch - test can we switch now */
741 if (strncmp(usercmd, "DIGD", 4) == 0) {
742 client_id = VGA_SWITCHEROO_IGD;
743 delay = true;
744 }
745
746 if (strncmp(usercmd, "DDIS", 4) == 0) {
747 client_id = VGA_SWITCHEROO_DIS;
748 delay = true;
749 }
750
751 if (strncmp(usercmd, "IGD", 3) == 0)
752 client_id = VGA_SWITCHEROO_IGD;
753
754 if (strncmp(usercmd, "DIS", 3) == 0)
755 client_id = VGA_SWITCHEROO_DIS;
756
757 if (strncmp(usercmd, "MIGD", 4) == 0) {
758 just_mux = true;
759 client_id = VGA_SWITCHEROO_IGD;
760 }
761 if (strncmp(usercmd, "MDIS", 4) == 0) {
762 just_mux = true;
763 client_id = VGA_SWITCHEROO_DIS;
764 }
765
766 if (client_id == VGA_SWITCHEROO_UNKNOWN_ID)
767 goto out;
768 client = find_client_from_id(&vgasr_priv.clients, client_id);
769 if (!client)
770 goto out;
771
772 vgasr_priv.delayed_switch_active = false;
773
774 if (just_mux) {
775 mutex_lock(&vgasr_priv.mux_hw_lock);
776 ret = vgasr_priv.handler->switchto(client_id);
777 mutex_unlock(&vgasr_priv.mux_hw_lock);
778 goto out;
779 }
780
781 if (client->active)
782 goto out;
783
784 /* okay we want a switch - test if devices are willing to switch */
785 can_switch = check_can_switch();
786
787 if (can_switch == false && delay == false)
788 goto out;
789
790 if (can_switch) {
791 ret = vga_switchto_stage1(client);
792 if (ret)
793 pr_err("switching failed stage 1 %d\n", ret);
794
795 ret = vga_switchto_stage2(client);
796 if (ret)
797 pr_err("switching failed stage 2 %d\n", ret);
798
799 } else {
800 pr_info("setting delayed switch to client %d\n", client->id);
801 vgasr_priv.delayed_switch_active = true;
802 vgasr_priv.delayed_client_id = client_id;
803
804 ret = vga_switchto_stage1(client);
805 if (ret)
806 pr_err("delayed switching stage 1 failed %d\n", ret);
807 }
808
809out:
810 mutex_unlock(&vgasr_mutex);
811 return cnt;
812}
813
814static const struct file_operations vga_switcheroo_debugfs_fops = {
815 .owner = THIS_MODULE,
816 .open = vga_switcheroo_debugfs_open,
817 .write = vga_switcheroo_debugfs_write,
818 .read = seq_read,
819 .llseek = seq_lseek,
820 .release = single_release,
821};
822
823static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
824{
825 debugfs_remove(priv->switch_file);
826 priv->switch_file = NULL;
827
828 debugfs_remove(priv->debugfs_root);
829 priv->debugfs_root = NULL;
830}
831
832static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
833{
834 static const char mp[] = "/sys/kernel/debug";
835
836 /* already initialised */
837 if (priv->debugfs_root)
838 return 0;
839 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
840
841 if (!priv->debugfs_root) {
842 pr_err("Cannot create %s/vgaswitcheroo\n", mp);
843 goto fail;
844 }
845
846 priv->switch_file = debugfs_create_file("switch", 0644,
847 priv->debugfs_root, NULL,
848 &vga_switcheroo_debugfs_fops);
849 if (!priv->switch_file) {
850 pr_err("cannot create %s/vgaswitcheroo/switch\n", mp);
851 goto fail;
852 }
853 return 0;
854fail:
855 vga_switcheroo_debugfs_fini(priv);
856 return -1;
857}
858
859/**
860 * vga_switcheroo_process_delayed_switch() - helper for delayed switching
861 *
862 * Process a delayed switch if one is pending. DRM drivers should call this
863 * from their ->lastclose callback.
864 *
865 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
866 * has unregistered in the meantime or if there are other clients blocking the
867 * switch. If the actual switch fails, an error is reported and 0 is returned.
868 */
869int vga_switcheroo_process_delayed_switch(void)
870{
871 struct vga_switcheroo_client *client;
872 int ret;
873 int err = -EINVAL;
874
875 mutex_lock(&vgasr_mutex);
876 if (!vgasr_priv.delayed_switch_active)
877 goto err;
878
879 pr_info("processing delayed switch to %d\n",
880 vgasr_priv.delayed_client_id);
881
882 client = find_client_from_id(&vgasr_priv.clients,
883 vgasr_priv.delayed_client_id);
884 if (!client || !check_can_switch())
885 goto err;
886
887 ret = vga_switchto_stage2(client);
888 if (ret)
889 pr_err("delayed switching failed stage 2 %d\n", ret);
890
891 vgasr_priv.delayed_switch_active = false;
892 err = 0;
893err:
894 mutex_unlock(&vgasr_mutex);
895 return err;
896}
897EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
898
899/**
900 * DOC: Driver power control
901 *
902 * In this mode of use, the discrete GPU automatically powers up and down at
903 * the discretion of the driver's runtime pm. On muxed machines, the user may
904 * still influence the muxer state by way of the debugfs interface, however
905 * the ON and OFF commands become a no-op for the discrete GPU.
906 *
907 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
908 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
909 * command line disables it.
910 *
911 * When the driver decides to power up or down, it notifies vga_switcheroo
912 * thereof so that it can (a) power the audio device on the GPU up or down,
913 * and (b) update its internal power state representation for the device.
914 * This is achieved by vga_switcheroo_set_dynamic_switch().
915 *
916 * After the GPU has been suspended, the handler needs to be called to cut
917 * power to the GPU. Likewise it needs to reinstate power before the GPU
918 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
919 * which augments the GPU's suspend/resume functions by the requisite
920 * calls to the handler.
921 *
922 * When the audio device resumes, the GPU needs to be woken. This is achieved
923 * by vga_switcheroo_init_domain_pm_optimus_hdmi_audio(), which augments the
924 * audio device's resume function.
925 *
926 * On muxed machines, if the mux is initially switched to the discrete GPU,
927 * the user ends up with a black screen when the GPU powers down after boot.
928 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
929 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
930 */
931
932static void vga_switcheroo_power_switch(struct pci_dev *pdev,
933 enum vga_switcheroo_state state)
934{
935 struct vga_switcheroo_client *client;
936
937 if (!vgasr_priv.handler->power_state)
938 return;
939
940 client = find_client_from_pci(&vgasr_priv.clients, pdev);
941 if (!client)
942 return;
943
944 if (!client->driver_power_control)
945 return;
946
947 vgasr_priv.handler->power_state(client->id, state);
948}
949
950/**
951 * vga_switcheroo_set_dynamic_switch() - helper for driver power control
952 * @pdev: client pci device
953 * @dynamic: new power state
954 *
955 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
956 * When the driver decides to power up or down, it notifies vga_switcheroo
957 * thereof using this helper so that it can (a) power the audio device on
958 * the GPU up or down, and (b) update its internal power state representation
959 * for the device.
960 */
961void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev,
962 enum vga_switcheroo_state dynamic)
963{
964 struct vga_switcheroo_client *client;
965
966 mutex_lock(&vgasr_mutex);
967 client = find_client_from_pci(&vgasr_priv.clients, pdev);
968 if (!client || !client->driver_power_control) {
969 mutex_unlock(&vgasr_mutex);
970 return;
971 }
972
973 client->pwr_state = dynamic;
974 set_audio_state(client->id, dynamic);
975 mutex_unlock(&vgasr_mutex);
976}
977EXPORT_SYMBOL(vga_switcheroo_set_dynamic_switch);
978
979/* switcheroo power domain */
980static int vga_switcheroo_runtime_suspend(struct device *dev)
981{
982 struct pci_dev *pdev = to_pci_dev(dev);
983 int ret;
984
985 ret = dev->bus->pm->runtime_suspend(dev);
986 if (ret)
987 return ret;
988 mutex_lock(&vgasr_mutex);
989 if (vgasr_priv.handler->switchto) {
990 mutex_lock(&vgasr_priv.mux_hw_lock);
991 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
992 mutex_unlock(&vgasr_priv.mux_hw_lock);
993 }
994 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
995 mutex_unlock(&vgasr_mutex);
996 return 0;
997}
998
999static int vga_switcheroo_runtime_resume(struct device *dev)
1000{
1001 struct pci_dev *pdev = to_pci_dev(dev);
1002 int ret;
1003
1004 mutex_lock(&vgasr_mutex);
1005 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
1006 mutex_unlock(&vgasr_mutex);
1007 ret = dev->bus->pm->runtime_resume(dev);
1008 if (ret)
1009 return ret;
1010
1011 return 0;
1012}
1013
1014/**
1015 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
1016 * @dev: vga client device
1017 * @domain: power domain
1018 *
1019 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
1020 * After the GPU has been suspended, the handler needs to be called to cut
1021 * power to the GPU. Likewise it needs to reinstate power before the GPU
1022 * can resume. To this end, this helper augments the suspend/resume functions
1023 * by the requisite calls to the handler. It needs only be called on platforms
1024 * where the power switch is separate to the device being powered down.
1025 */
1026int vga_switcheroo_init_domain_pm_ops(struct device *dev,
1027 struct dev_pm_domain *domain)
1028{
1029 /* copy over all the bus versions */
1030 if (dev->bus && dev->bus->pm) {
1031 domain->ops = *dev->bus->pm;
1032 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
1033 domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
1034
1035 dev_pm_domain_set(dev, domain);
1036 return 0;
1037 }
1038 dev_pm_domain_set(dev, NULL);
1039 return -EINVAL;
1040}
1041EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
1042
1043void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
1044{
1045 dev_pm_domain_set(dev, NULL);
1046}
1047EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);
1048
1049static int vga_switcheroo_runtime_resume_hdmi_audio(struct device *dev)
1050{
1051 struct pci_dev *pdev = to_pci_dev(dev);
1052 struct vga_switcheroo_client *client;
1053 struct device *video_dev = NULL;
1054 int ret;
1055
1056 /* we need to check if we have to switch back on the video
1057 device so the audio device can come back */
1058 mutex_lock(&vgasr_mutex);
1059 list_for_each_entry(client, &vgasr_priv.clients, list) {
1060 if (PCI_SLOT(client->pdev->devfn) == PCI_SLOT(pdev->devfn) &&
1061 client_is_vga(client)) {
1062 video_dev = &client->pdev->dev;
1063 break;
1064 }
1065 }
1066 mutex_unlock(&vgasr_mutex);
1067
1068 if (video_dev) {
1069 ret = pm_runtime_get_sync(video_dev);
1070 if (ret && ret != 1)
1071 return ret;
1072 }
1073 ret = dev->bus->pm->runtime_resume(dev);
1074
1075 /* put the reference for the gpu */
1076 if (video_dev) {
1077 pm_runtime_mark_last_busy(video_dev);
1078 pm_runtime_put_autosuspend(video_dev);
1079 }
1080 return ret;
1081}
1082
1083/**
1084 * vga_switcheroo_init_domain_pm_optimus_hdmi_audio() - helper for driver
1085 * power control
1086 * @dev: audio client device
1087 * @domain: power domain
1088 *
1089 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
1090 * When the audio device resumes, the GPU needs to be woken. This helper
1091 * augments the audio device's resume function to do that.
1092 *
1093 * Return: 0 on success, -EINVAL if no power management operations are
1094 * defined for this device.
1095 */
1096int
1097vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
1098 struct dev_pm_domain *domain)
1099{
1100 /* copy over all the bus versions */
1101 if (dev->bus && dev->bus->pm) {
1102 domain->ops = *dev->bus->pm;
1103 domain->ops.runtime_resume =
1104 vga_switcheroo_runtime_resume_hdmi_audio;
1105
1106 dev_pm_domain_set(dev, domain);
1107 return 0;
1108 }
1109 dev_pm_domain_set(dev, NULL);
1110 return -EINVAL;
1111}
1112EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
1/*
2 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
3 *
4 * Copyright (c) 2010 Red Hat Inc.
5 * Author : Dave Airlie <airlied@redhat.com>
6 *
7 * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the next
17 * paragraph) shall be included in all copies or substantial portions of the
18 * Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 * DEALINGS
27 * IN THE SOFTWARE.
28 *
29 */
30
31#define pr_fmt(fmt) "vga_switcheroo: " fmt
32
33#include <linux/apple-gmux.h>
34#include <linux/console.h>
35#include <linux/debugfs.h>
36#include <linux/fb.h>
37#include <linux/fs.h>
38#include <linux/module.h>
39#include <linux/pci.h>
40#include <linux/pm_domain.h>
41#include <linux/pm_runtime.h>
42#include <linux/seq_file.h>
43#include <linux/uaccess.h>
44#include <linux/vgaarb.h>
45#include <linux/vga_switcheroo.h>
46
47/**
48 * DOC: Overview
49 *
50 * vga_switcheroo is the Linux subsystem for laptop hybrid graphics.
51 * These come in two flavors:
52 *
53 * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs.
54 * * muxless: Dual GPUs but only one of them is connected to outputs.
55 * The other one is merely used to offload rendering, its results
56 * are copied over PCIe into the framebuffer. On Linux this is
57 * supported with DRI PRIME.
58 *
59 * Hybrid graphics started to appear in the late Naughties and were initially
60 * all muxed. Newer laptops moved to a muxless architecture for cost reasons.
61 * A notable exception is the MacBook Pro which continues to use a mux.
62 * Muxes come with varying capabilities: Some switch only the panel, others
63 * can also switch external displays. Some switch all display pins at once
64 * while others can switch just the DDC lines. (To allow EDID probing
65 * for the inactive GPU.) Also, muxes are often used to cut power to the
66 * discrete GPU while it is not used.
67 *
68 * DRM drivers register GPUs with vga_switcheroo, these are henceforth called
69 * clients. The mux is called the handler. Muxless machines also register a
70 * handler to control the power state of the discrete GPU, its ->switchto
71 * callback is a no-op for obvious reasons. The discrete GPU is often equipped
72 * with an HDA controller for the HDMI/DP audio signal, this will also
73 * register as a client so that vga_switcheroo can take care of the correct
74 * suspend/resume order when changing the discrete GPU's power state. In total
75 * there can thus be up to three clients: Two vga clients (GPUs) and one audio
76 * client (on the discrete GPU). The code is mostly prepared to support
77 * machines with more than two GPUs should they become available.
78 *
79 * The GPU to which the outputs are currently switched is called the
80 * active client in vga_switcheroo parlance. The GPU not in use is the
81 * inactive client. When the inactive client's DRM driver is loaded,
82 * it will be unable to probe the panel's EDID and hence depends on
83 * VBIOS to provide its display modes. If the VBIOS modes are bogus or
84 * if there is no VBIOS at all (which is common on the MacBook Pro),
85 * a client may alternatively request that the DDC lines are temporarily
86 * switched to it, provided that the handler supports this. Switching
87 * only the DDC lines and not the entire output avoids unnecessary
88 * flickering.
89 */
90
91/**
92 * struct vga_switcheroo_client - registered client
93 * @pdev: client pci device
94 * @fb_info: framebuffer to which console is remapped on switching
95 * @pwr_state: current power state
96 * @ops: client callbacks
97 * @id: client identifier. Determining the id requires the handler,
98 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
99 * and later given their true id in vga_switcheroo_enable()
100 * @active: whether the outputs are currently switched to this client
101 * @driver_power_control: whether power state is controlled by the driver's
102 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
103 * interface is a no-op so as not to interfere with runtime pm
104 * @list: client list
105 *
106 * Registered client. A client can be either a GPU or an audio device on a GPU.
107 * For audio clients, the @fb_info, @active and @driver_power_control members
108 * are bogus.
109 */
110struct vga_switcheroo_client {
111 struct pci_dev *pdev;
112 struct fb_info *fb_info;
113 enum vga_switcheroo_state pwr_state;
114 const struct vga_switcheroo_client_ops *ops;
115 enum vga_switcheroo_client_id id;
116 bool active;
117 bool driver_power_control;
118 struct list_head list;
119};
120
121/*
122 * protects access to struct vgasr_priv
123 */
124static DEFINE_MUTEX(vgasr_mutex);
125
126/**
127 * struct vgasr_priv - vga_switcheroo private data
128 * @active: whether vga_switcheroo is enabled.
129 * Prerequisite is the registration of two GPUs and a handler
130 * @delayed_switch_active: whether a delayed switch is pending
131 * @delayed_client_id: client to which a delayed switch is pending
132 * @debugfs_root: directory for vga_switcheroo debugfs interface
133 * @switch_file: file for vga_switcheroo debugfs interface
134 * @registered_clients: number of registered GPUs
135 * (counting only vga clients, not audio clients)
136 * @clients: list of registered clients
137 * @handler: registered handler
138 * @handler_flags: flags of registered handler
139 * @mux_hw_lock: protects mux state
140 * (in particular while DDC lines are temporarily switched)
141 * @old_ddc_owner: client to which DDC lines will be switched back on unlock
142 *
143 * vga_switcheroo private data. Currently only one vga_switcheroo instance
144 * per system is supported.
145 */
146struct vgasr_priv {
147 bool active;
148 bool delayed_switch_active;
149 enum vga_switcheroo_client_id delayed_client_id;
150
151 struct dentry *debugfs_root;
152 struct dentry *switch_file;
153
154 int registered_clients;
155 struct list_head clients;
156
157 const struct vga_switcheroo_handler *handler;
158 enum vga_switcheroo_handler_flags_t handler_flags;
159 struct mutex mux_hw_lock;
160 int old_ddc_owner;
161};
162
163#define ID_BIT_AUDIO 0x100
164#define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
165#define client_is_vga(c) ((c)->id == VGA_SWITCHEROO_UNKNOWN_ID || \
166 !client_is_audio(c))
167#define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
168
169static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
170static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
171
172/* only one switcheroo per system */
173static struct vgasr_priv vgasr_priv = {
174 .clients = LIST_HEAD_INIT(vgasr_priv.clients),
175 .mux_hw_lock = __MUTEX_INITIALIZER(vgasr_priv.mux_hw_lock),
176};
177
178static bool vga_switcheroo_ready(void)
179{
180 /* we're ready if we get two clients + handler */
181 return !vgasr_priv.active &&
182 vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
183}
184
185static void vga_switcheroo_enable(void)
186{
187 int ret;
188 struct vga_switcheroo_client *client;
189
190 /* call the handler to init */
191 if (vgasr_priv.handler->init)
192 vgasr_priv.handler->init();
193
194 list_for_each_entry(client, &vgasr_priv.clients, list) {
195 if (client->id != VGA_SWITCHEROO_UNKNOWN_ID)
196 continue;
197 ret = vgasr_priv.handler->get_client_id(client->pdev);
198 if (ret < 0)
199 return;
200
201 client->id = ret;
202 }
203 vga_switcheroo_debugfs_init(&vgasr_priv);
204 vgasr_priv.active = true;
205}
206
207/**
208 * vga_switcheroo_register_handler() - register handler
209 * @handler: handler callbacks
210 * @handler_flags: handler flags
211 *
212 * Register handler. Enable vga_switcheroo if two vga clients have already
213 * registered.
214 *
215 * Return: 0 on success, -EINVAL if a handler was already registered.
216 */
217int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
218 enum vga_switcheroo_handler_flags_t handler_flags)
219{
220 mutex_lock(&vgasr_mutex);
221 if (vgasr_priv.handler) {
222 mutex_unlock(&vgasr_mutex);
223 return -EINVAL;
224 }
225
226 vgasr_priv.handler = handler;
227 vgasr_priv.handler_flags = handler_flags;
228 if (vga_switcheroo_ready()) {
229 pr_info("enabled\n");
230 vga_switcheroo_enable();
231 }
232 mutex_unlock(&vgasr_mutex);
233 return 0;
234}
235EXPORT_SYMBOL(vga_switcheroo_register_handler);
236
237/**
238 * vga_switcheroo_unregister_handler() - unregister handler
239 *
240 * Unregister handler. Disable vga_switcheroo.
241 */
242void vga_switcheroo_unregister_handler(void)
243{
244 mutex_lock(&vgasr_mutex);
245 mutex_lock(&vgasr_priv.mux_hw_lock);
246 vgasr_priv.handler_flags = 0;
247 vgasr_priv.handler = NULL;
248 if (vgasr_priv.active) {
249 pr_info("disabled\n");
250 vga_switcheroo_debugfs_fini(&vgasr_priv);
251 vgasr_priv.active = false;
252 }
253 mutex_unlock(&vgasr_priv.mux_hw_lock);
254 mutex_unlock(&vgasr_mutex);
255}
256EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
257
258/**
259 * vga_switcheroo_handler_flags() - obtain handler flags
260 *
261 * Helper for clients to obtain the handler flags bitmask.
262 *
263 * Return: Handler flags. A value of 0 means that no handler is registered
264 * or that the handler has no special capabilities.
265 */
266enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void)
267{
268 return vgasr_priv.handler_flags;
269}
270EXPORT_SYMBOL(vga_switcheroo_handler_flags);
271
272static int register_client(struct pci_dev *pdev,
273 const struct vga_switcheroo_client_ops *ops,
274 enum vga_switcheroo_client_id id, bool active,
275 bool driver_power_control)
276{
277 struct vga_switcheroo_client *client;
278
279 client = kzalloc(sizeof(*client), GFP_KERNEL);
280 if (!client)
281 return -ENOMEM;
282
283 client->pwr_state = VGA_SWITCHEROO_ON;
284 client->pdev = pdev;
285 client->ops = ops;
286 client->id = id;
287 client->active = active;
288 client->driver_power_control = driver_power_control;
289
290 mutex_lock(&vgasr_mutex);
291 list_add_tail(&client->list, &vgasr_priv.clients);
292 if (client_is_vga(client))
293 vgasr_priv.registered_clients++;
294
295 if (vga_switcheroo_ready()) {
296 pr_info("enabled\n");
297 vga_switcheroo_enable();
298 }
299 mutex_unlock(&vgasr_mutex);
300 return 0;
301}
302
303/**
304 * vga_switcheroo_register_client - register vga client
305 * @pdev: client pci device
306 * @ops: client callbacks
307 * @driver_power_control: whether power state is controlled by the driver's
308 * runtime pm
309 *
310 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
311 * handler have already registered. The power state of the client is assumed
312 * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called
313 * to ensure that all prerequisites are met.
314 *
315 * Return: 0 on success, -ENOMEM on memory allocation error.
316 */
317int vga_switcheroo_register_client(struct pci_dev *pdev,
318 const struct vga_switcheroo_client_ops *ops,
319 bool driver_power_control)
320{
321 return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID,
322 pdev == vga_default_device(),
323 driver_power_control);
324}
325EXPORT_SYMBOL(vga_switcheroo_register_client);
326
327/**
328 * vga_switcheroo_register_audio_client - register audio client
329 * @pdev: client pci device
330 * @ops: client callbacks
331 * @id: client identifier
332 *
333 * Register audio client (audio device on a GPU). The power state of the
334 * client is assumed to be ON. Beforehand, vga_switcheroo_client_probe_defer()
335 * shall be called to ensure that all prerequisites are met.
336 *
337 * Return: 0 on success, -ENOMEM on memory allocation error.
338 */
339int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
340 const struct vga_switcheroo_client_ops *ops,
341 enum vga_switcheroo_client_id id)
342{
343 return register_client(pdev, ops, id | ID_BIT_AUDIO, false, false);
344}
345EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
346
347static struct vga_switcheroo_client *
348find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
349{
350 struct vga_switcheroo_client *client;
351
352 list_for_each_entry(client, head, list)
353 if (client->pdev == pdev)
354 return client;
355 return NULL;
356}
357
358static struct vga_switcheroo_client *
359find_client_from_id(struct list_head *head,
360 enum vga_switcheroo_client_id client_id)
361{
362 struct vga_switcheroo_client *client;
363
364 list_for_each_entry(client, head, list)
365 if (client->id == client_id)
366 return client;
367 return NULL;
368}
369
370static struct vga_switcheroo_client *
371find_active_client(struct list_head *head)
372{
373 struct vga_switcheroo_client *client;
374
375 list_for_each_entry(client, head, list)
376 if (client->active)
377 return client;
378 return NULL;
379}
380
381/**
382 * vga_switcheroo_client_probe_defer() - whether to defer probing a given client
383 * @pdev: client pci device
384 *
385 * Determine whether any prerequisites are not fulfilled to probe a given
386 * client. Drivers shall invoke this early on in their ->probe callback
387 * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
388 * register the client ere thou hast called this.
389 *
390 * Return: %true if probing should be deferred, otherwise %false.
391 */
392bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
393{
394 if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
395 /*
396 * apple-gmux is needed on pre-retina MacBook Pro
397 * to probe the panel if pdev is the inactive GPU.
398 */
399 if (apple_gmux_present() && pdev != vga_default_device() &&
400 !vgasr_priv.handler_flags)
401 return true;
402 }
403
404 return false;
405}
406EXPORT_SYMBOL(vga_switcheroo_client_probe_defer);
407
408/**
409 * vga_switcheroo_get_client_state() - obtain power state of a given client
410 * @pdev: client pci device
411 *
412 * Obtain power state of a given client as seen from vga_switcheroo.
413 * The function is only called from hda_intel.c.
414 *
415 * Return: Power state.
416 */
417enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev)
418{
419 struct vga_switcheroo_client *client;
420 enum vga_switcheroo_state ret;
421
422 mutex_lock(&vgasr_mutex);
423 client = find_client_from_pci(&vgasr_priv.clients, pdev);
424 if (!client)
425 ret = VGA_SWITCHEROO_NOT_FOUND;
426 else
427 ret = client->pwr_state;
428 mutex_unlock(&vgasr_mutex);
429 return ret;
430}
431EXPORT_SYMBOL(vga_switcheroo_get_client_state);
432
433/**
434 * vga_switcheroo_unregister_client() - unregister client
435 * @pdev: client pci device
436 *
437 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
438 */
439void vga_switcheroo_unregister_client(struct pci_dev *pdev)
440{
441 struct vga_switcheroo_client *client;
442
443 mutex_lock(&vgasr_mutex);
444 client = find_client_from_pci(&vgasr_priv.clients, pdev);
445 if (client) {
446 if (client_is_vga(client))
447 vgasr_priv.registered_clients--;
448 list_del(&client->list);
449 kfree(client);
450 }
451 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
452 pr_info("disabled\n");
453 vga_switcheroo_debugfs_fini(&vgasr_priv);
454 vgasr_priv.active = false;
455 }
456 mutex_unlock(&vgasr_mutex);
457}
458EXPORT_SYMBOL(vga_switcheroo_unregister_client);
459
460/**
461 * vga_switcheroo_client_fb_set() - set framebuffer of a given client
462 * @pdev: client pci device
463 * @info: framebuffer
464 *
465 * Set framebuffer of a given client. The console will be remapped to this
466 * on switching.
467 */
468void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
469 struct fb_info *info)
470{
471 struct vga_switcheroo_client *client;
472
473 mutex_lock(&vgasr_mutex);
474 client = find_client_from_pci(&vgasr_priv.clients, pdev);
475 if (client)
476 client->fb_info = info;
477 mutex_unlock(&vgasr_mutex);
478}
479EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
480
481/**
482 * vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client
483 * @pdev: client pci device
484 *
485 * Temporarily switch DDC lines to the client identified by @pdev
486 * (but leave the outputs otherwise switched to where they are).
487 * This allows the inactive client to probe EDID. The DDC lines must
488 * afterwards be switched back by calling vga_switcheroo_unlock_ddc(),
489 * even if this function returns an error.
490 *
491 * Return: Previous DDC owner on success or a negative int on error.
492 * Specifically, %-ENODEV if no handler has registered or if the handler
493 * does not support switching the DDC lines. Also, a negative value
494 * returned by the handler is propagated back to the caller.
495 * The return value has merely an informational purpose for any caller
496 * which might be interested in it. It is acceptable to ignore the return
497 * value and simply rely on the result of the subsequent EDID probe,
498 * which will be %NULL if DDC switching failed.
499 */
500int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
501{
502 enum vga_switcheroo_client_id id;
503
504 mutex_lock(&vgasr_priv.mux_hw_lock);
505 if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) {
506 vgasr_priv.old_ddc_owner = -ENODEV;
507 return -ENODEV;
508 }
509
510 id = vgasr_priv.handler->get_client_id(pdev);
511 vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id);
512 return vgasr_priv.old_ddc_owner;
513}
514EXPORT_SYMBOL(vga_switcheroo_lock_ddc);
515
516/**
517 * vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner
518 * @pdev: client pci device
519 *
520 * Switch DDC lines back to the previous owner after calling
521 * vga_switcheroo_lock_ddc(). This must be called even if
522 * vga_switcheroo_lock_ddc() returned an error.
523 *
524 * Return: Previous DDC owner on success (i.e. the client identifier of @pdev)
525 * or a negative int on error.
526 * Specifically, %-ENODEV if no handler has registered or if the handler
527 * does not support switching the DDC lines. Also, a negative value
528 * returned by the handler is propagated back to the caller.
529 * Finally, invoking this function without calling vga_switcheroo_lock_ddc()
530 * first is not allowed and will result in %-EINVAL.
531 */
532int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
533{
534 enum vga_switcheroo_client_id id;
535 int ret = vgasr_priv.old_ddc_owner;
536
537 if (WARN_ON_ONCE(!mutex_is_locked(&vgasr_priv.mux_hw_lock)))
538 return -EINVAL;
539
540 if (vgasr_priv.old_ddc_owner >= 0) {
541 id = vgasr_priv.handler->get_client_id(pdev);
542 if (vgasr_priv.old_ddc_owner != id)
543 ret = vgasr_priv.handler->switch_ddc(
544 vgasr_priv.old_ddc_owner);
545 }
546 mutex_unlock(&vgasr_priv.mux_hw_lock);
547 return ret;
548}
549EXPORT_SYMBOL(vga_switcheroo_unlock_ddc);
550
551/**
552 * DOC: Manual switching and manual power control
553 *
554 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
555 * can be read to retrieve the current vga_switcheroo state and commands
556 * can be written to it to change the state. The file appears as soon as
557 * two GPU drivers and one handler have registered with vga_switcheroo.
558 * The following commands are understood:
559 *
560 * * OFF: Power off the device not in use.
561 * * ON: Power on the device not in use.
562 * * IGD: Switch to the integrated graphics device.
563 * Power on the integrated GPU if necessary, power off the discrete GPU.
564 * Prerequisite is that no user space processes (e.g. Xorg, alsactl)
565 * have opened device files of the GPUs or the audio client. If the
566 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
567 * and /dev/snd/controlC1 to identify processes blocking the switch.
568 * * DIS: Switch to the discrete graphics device.
569 * * DIGD: Delayed switch to the integrated graphics device.
570 * This will perform the switch once the last user space process has
571 * closed the device files of the GPUs and the audio client.
572 * * DDIS: Delayed switch to the discrete graphics device.
573 * * MIGD: Mux-only switch to the integrated graphics device.
574 * Does not remap console or change the power state of either gpu.
575 * If the integrated GPU is currently off, the screen will turn black.
576 * If it is on, the screen will show whatever happens to be in VRAM.
577 * Either way, the user has to blindly enter the command to switch back.
578 * * MDIS: Mux-only switch to the discrete graphics device.
579 *
580 * For GPUs whose power state is controlled by the driver's runtime pm,
581 * the ON and OFF commands are a no-op (see next section).
582 *
583 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
584 * should not be used.
585 */
586
587static int vga_switcheroo_show(struct seq_file *m, void *v)
588{
589 struct vga_switcheroo_client *client;
590 int i = 0;
591
592 mutex_lock(&vgasr_mutex);
593 list_for_each_entry(client, &vgasr_priv.clients, list) {
594 seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
595 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" :
596 "IGD",
597 client_is_vga(client) ? "" : "-Audio",
598 client->active ? '+' : ' ',
599 client->driver_power_control ? "Dyn" : "",
600 client->pwr_state ? "Pwr" : "Off",
601 pci_name(client->pdev));
602 i++;
603 }
604 mutex_unlock(&vgasr_mutex);
605 return 0;
606}
607
608static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
609{
610 return single_open(file, vga_switcheroo_show, NULL);
611}
612
613static int vga_switchon(struct vga_switcheroo_client *client)
614{
615 if (client->driver_power_control)
616 return 0;
617 if (vgasr_priv.handler->power_state)
618 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
619 /* call the driver callback to turn on device */
620 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
621 client->pwr_state = VGA_SWITCHEROO_ON;
622 return 0;
623}
624
625static int vga_switchoff(struct vga_switcheroo_client *client)
626{
627 if (client->driver_power_control)
628 return 0;
629 /* call the driver callback to turn off device */
630 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
631 if (vgasr_priv.handler->power_state)
632 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
633 client->pwr_state = VGA_SWITCHEROO_OFF;
634 return 0;
635}
636
637static void set_audio_state(enum vga_switcheroo_client_id id,
638 enum vga_switcheroo_state state)
639{
640 struct vga_switcheroo_client *client;
641
642 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
643 if (client && client->pwr_state != state) {
644 client->ops->set_gpu_state(client->pdev, state);
645 client->pwr_state = state;
646 }
647}
648
649/* stage one happens before delay */
650static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
651{
652 struct vga_switcheroo_client *active;
653
654 active = find_active_client(&vgasr_priv.clients);
655 if (!active)
656 return 0;
657
658 if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
659 vga_switchon(new_client);
660
661 vga_set_default_device(new_client->pdev);
662 return 0;
663}
664
665/* post delay */
666static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
667{
668 int ret;
669 struct vga_switcheroo_client *active;
670
671 active = find_active_client(&vgasr_priv.clients);
672 if (!active)
673 return 0;
674
675 active->active = false;
676
677 set_audio_state(active->id, VGA_SWITCHEROO_OFF);
678
679 if (new_client->fb_info) {
680 struct fb_event event;
681
682 console_lock();
683 event.info = new_client->fb_info;
684 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
685 console_unlock();
686 }
687
688 mutex_lock(&vgasr_priv.mux_hw_lock);
689 ret = vgasr_priv.handler->switchto(new_client->id);
690 mutex_unlock(&vgasr_priv.mux_hw_lock);
691 if (ret)
692 return ret;
693
694 if (new_client->ops->reprobe)
695 new_client->ops->reprobe(new_client->pdev);
696
697 if (active->pwr_state == VGA_SWITCHEROO_ON)
698 vga_switchoff(active);
699
700 set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
701
702 new_client->active = true;
703 return 0;
704}
705
706static bool check_can_switch(void)
707{
708 struct vga_switcheroo_client *client;
709
710 list_for_each_entry(client, &vgasr_priv.clients, list) {
711 if (!client->ops->can_switch(client->pdev)) {
712 pr_err("client %x refused switch\n", client->id);
713 return false;
714 }
715 }
716 return true;
717}
718
719static ssize_t
720vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
721 size_t cnt, loff_t *ppos)
722{
723 char usercmd[64];
724 int ret;
725 bool delay = false, can_switch;
726 bool just_mux = false;
727 enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID;
728 struct vga_switcheroo_client *client = NULL;
729
730 if (cnt > 63)
731 cnt = 63;
732
733 if (copy_from_user(usercmd, ubuf, cnt))
734 return -EFAULT;
735
736 mutex_lock(&vgasr_mutex);
737
738 if (!vgasr_priv.active) {
739 cnt = -EINVAL;
740 goto out;
741 }
742
743 /* pwr off the device not in use */
744 if (strncmp(usercmd, "OFF", 3) == 0) {
745 list_for_each_entry(client, &vgasr_priv.clients, list) {
746 if (client->active || client_is_audio(client))
747 continue;
748 if (client->driver_power_control)
749 continue;
750 set_audio_state(client->id, VGA_SWITCHEROO_OFF);
751 if (client->pwr_state == VGA_SWITCHEROO_ON)
752 vga_switchoff(client);
753 }
754 goto out;
755 }
756 /* pwr on the device not in use */
757 if (strncmp(usercmd, "ON", 2) == 0) {
758 list_for_each_entry(client, &vgasr_priv.clients, list) {
759 if (client->active || client_is_audio(client))
760 continue;
761 if (client->driver_power_control)
762 continue;
763 if (client->pwr_state == VGA_SWITCHEROO_OFF)
764 vga_switchon(client);
765 set_audio_state(client->id, VGA_SWITCHEROO_ON);
766 }
767 goto out;
768 }
769
770 /* request a delayed switch - test can we switch now */
771 if (strncmp(usercmd, "DIGD", 4) == 0) {
772 client_id = VGA_SWITCHEROO_IGD;
773 delay = true;
774 }
775
776 if (strncmp(usercmd, "DDIS", 4) == 0) {
777 client_id = VGA_SWITCHEROO_DIS;
778 delay = true;
779 }
780
781 if (strncmp(usercmd, "IGD", 3) == 0)
782 client_id = VGA_SWITCHEROO_IGD;
783
784 if (strncmp(usercmd, "DIS", 3) == 0)
785 client_id = VGA_SWITCHEROO_DIS;
786
787 if (strncmp(usercmd, "MIGD", 4) == 0) {
788 just_mux = true;
789 client_id = VGA_SWITCHEROO_IGD;
790 }
791 if (strncmp(usercmd, "MDIS", 4) == 0) {
792 just_mux = true;
793 client_id = VGA_SWITCHEROO_DIS;
794 }
795
796 if (client_id == VGA_SWITCHEROO_UNKNOWN_ID)
797 goto out;
798 client = find_client_from_id(&vgasr_priv.clients, client_id);
799 if (!client)
800 goto out;
801
802 vgasr_priv.delayed_switch_active = false;
803
804 if (just_mux) {
805 mutex_lock(&vgasr_priv.mux_hw_lock);
806 ret = vgasr_priv.handler->switchto(client_id);
807 mutex_unlock(&vgasr_priv.mux_hw_lock);
808 goto out;
809 }
810
811 if (client->active)
812 goto out;
813
814 /* okay we want a switch - test if devices are willing to switch */
815 can_switch = check_can_switch();
816
817 if (can_switch == false && delay == false)
818 goto out;
819
820 if (can_switch) {
821 ret = vga_switchto_stage1(client);
822 if (ret)
823 pr_err("switching failed stage 1 %d\n", ret);
824
825 ret = vga_switchto_stage2(client);
826 if (ret)
827 pr_err("switching failed stage 2 %d\n", ret);
828
829 } else {
830 pr_info("setting delayed switch to client %d\n", client->id);
831 vgasr_priv.delayed_switch_active = true;
832 vgasr_priv.delayed_client_id = client_id;
833
834 ret = vga_switchto_stage1(client);
835 if (ret)
836 pr_err("delayed switching stage 1 failed %d\n", ret);
837 }
838
839out:
840 mutex_unlock(&vgasr_mutex);
841 return cnt;
842}
843
844static const struct file_operations vga_switcheroo_debugfs_fops = {
845 .owner = THIS_MODULE,
846 .open = vga_switcheroo_debugfs_open,
847 .write = vga_switcheroo_debugfs_write,
848 .read = seq_read,
849 .llseek = seq_lseek,
850 .release = single_release,
851};
852
853static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
854{
855 debugfs_remove(priv->switch_file);
856 priv->switch_file = NULL;
857
858 debugfs_remove(priv->debugfs_root);
859 priv->debugfs_root = NULL;
860}
861
862static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
863{
864 static const char mp[] = "/sys/kernel/debug";
865
866 /* already initialised */
867 if (priv->debugfs_root)
868 return 0;
869 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
870
871 if (!priv->debugfs_root) {
872 pr_err("Cannot create %s/vgaswitcheroo\n", mp);
873 goto fail;
874 }
875
876 priv->switch_file = debugfs_create_file("switch", 0644,
877 priv->debugfs_root, NULL,
878 &vga_switcheroo_debugfs_fops);
879 if (!priv->switch_file) {
880 pr_err("cannot create %s/vgaswitcheroo/switch\n", mp);
881 goto fail;
882 }
883 return 0;
884fail:
885 vga_switcheroo_debugfs_fini(priv);
886 return -1;
887}
888
889/**
890 * vga_switcheroo_process_delayed_switch() - helper for delayed switching
891 *
892 * Process a delayed switch if one is pending. DRM drivers should call this
893 * from their ->lastclose callback.
894 *
895 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
896 * has unregistered in the meantime or if there are other clients blocking the
897 * switch. If the actual switch fails, an error is reported and 0 is returned.
898 */
899int vga_switcheroo_process_delayed_switch(void)
900{
901 struct vga_switcheroo_client *client;
902 int ret;
903 int err = -EINVAL;
904
905 mutex_lock(&vgasr_mutex);
906 if (!vgasr_priv.delayed_switch_active)
907 goto err;
908
909 pr_info("processing delayed switch to %d\n",
910 vgasr_priv.delayed_client_id);
911
912 client = find_client_from_id(&vgasr_priv.clients,
913 vgasr_priv.delayed_client_id);
914 if (!client || !check_can_switch())
915 goto err;
916
917 ret = vga_switchto_stage2(client);
918 if (ret)
919 pr_err("delayed switching failed stage 2 %d\n", ret);
920
921 vgasr_priv.delayed_switch_active = false;
922 err = 0;
923err:
924 mutex_unlock(&vgasr_mutex);
925 return err;
926}
927EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
928
929/**
930 * DOC: Driver power control
931 *
932 * In this mode of use, the discrete GPU automatically powers up and down at
933 * the discretion of the driver's runtime pm. On muxed machines, the user may
934 * still influence the muxer state by way of the debugfs interface, however
935 * the ON and OFF commands become a no-op for the discrete GPU.
936 *
937 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
938 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
939 * command line disables it.
940 *
941 * When the driver decides to power up or down, it notifies vga_switcheroo
942 * thereof so that it can (a) power the audio device on the GPU up or down,
943 * and (b) update its internal power state representation for the device.
944 * This is achieved by vga_switcheroo_set_dynamic_switch().
945 *
946 * After the GPU has been suspended, the handler needs to be called to cut
947 * power to the GPU. Likewise it needs to reinstate power before the GPU
948 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
949 * which augments the GPU's suspend/resume functions by the requisite
950 * calls to the handler.
951 *
952 * When the audio device resumes, the GPU needs to be woken. This is achieved
953 * by vga_switcheroo_init_domain_pm_optimus_hdmi_audio(), which augments the
954 * audio device's resume function.
955 *
956 * On muxed machines, if the mux is initially switched to the discrete GPU,
957 * the user ends up with a black screen when the GPU powers down after boot.
958 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
959 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
960 */
961
962static void vga_switcheroo_power_switch(struct pci_dev *pdev,
963 enum vga_switcheroo_state state)
964{
965 struct vga_switcheroo_client *client;
966
967 if (!vgasr_priv.handler->power_state)
968 return;
969
970 client = find_client_from_pci(&vgasr_priv.clients, pdev);
971 if (!client)
972 return;
973
974 if (!client->driver_power_control)
975 return;
976
977 vgasr_priv.handler->power_state(client->id, state);
978}
979
980/**
981 * vga_switcheroo_set_dynamic_switch() - helper for driver power control
982 * @pdev: client pci device
983 * @dynamic: new power state
984 *
985 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
986 * When the driver decides to power up or down, it notifies vga_switcheroo
987 * thereof using this helper so that it can (a) power the audio device on
988 * the GPU up or down, and (b) update its internal power state representation
989 * for the device.
990 */
991void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev,
992 enum vga_switcheroo_state dynamic)
993{
994 struct vga_switcheroo_client *client;
995
996 mutex_lock(&vgasr_mutex);
997 client = find_client_from_pci(&vgasr_priv.clients, pdev);
998 if (!client || !client->driver_power_control) {
999 mutex_unlock(&vgasr_mutex);
1000 return;
1001 }
1002
1003 client->pwr_state = dynamic;
1004 set_audio_state(client->id, dynamic);
1005 mutex_unlock(&vgasr_mutex);
1006}
1007EXPORT_SYMBOL(vga_switcheroo_set_dynamic_switch);
1008
1009/* switcheroo power domain */
1010static int vga_switcheroo_runtime_suspend(struct device *dev)
1011{
1012 struct pci_dev *pdev = to_pci_dev(dev);
1013 int ret;
1014
1015 ret = dev->bus->pm->runtime_suspend(dev);
1016 if (ret)
1017 return ret;
1018 mutex_lock(&vgasr_mutex);
1019 if (vgasr_priv.handler->switchto) {
1020 mutex_lock(&vgasr_priv.mux_hw_lock);
1021 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
1022 mutex_unlock(&vgasr_priv.mux_hw_lock);
1023 }
1024 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
1025 mutex_unlock(&vgasr_mutex);
1026 return 0;
1027}
1028
1029static int vga_switcheroo_runtime_resume(struct device *dev)
1030{
1031 struct pci_dev *pdev = to_pci_dev(dev);
1032 int ret;
1033
1034 mutex_lock(&vgasr_mutex);
1035 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
1036 mutex_unlock(&vgasr_mutex);
1037 ret = dev->bus->pm->runtime_resume(dev);
1038 if (ret)
1039 return ret;
1040
1041 return 0;
1042}
1043
1044/**
1045 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
1046 * @dev: vga client device
1047 * @domain: power domain
1048 *
1049 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
1050 * After the GPU has been suspended, the handler needs to be called to cut
1051 * power to the GPU. Likewise it needs to reinstate power before the GPU
1052 * can resume. To this end, this helper augments the suspend/resume functions
1053 * by the requisite calls to the handler. It needs only be called on platforms
1054 * where the power switch is separate to the device being powered down.
1055 */
1056int vga_switcheroo_init_domain_pm_ops(struct device *dev,
1057 struct dev_pm_domain *domain)
1058{
1059 /* copy over all the bus versions */
1060 if (dev->bus && dev->bus->pm) {
1061 domain->ops = *dev->bus->pm;
1062 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
1063 domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
1064
1065 dev_pm_domain_set(dev, domain);
1066 return 0;
1067 }
1068 dev_pm_domain_set(dev, NULL);
1069 return -EINVAL;
1070}
1071EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
1072
1073void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
1074{
1075 dev_pm_domain_set(dev, NULL);
1076}
1077EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);
1078
1079static int vga_switcheroo_runtime_resume_hdmi_audio(struct device *dev)
1080{
1081 struct pci_dev *pdev = to_pci_dev(dev);
1082 struct vga_switcheroo_client *client;
1083 struct device *video_dev = NULL;
1084 int ret;
1085
1086 /* we need to check if we have to switch back on the video
1087 device so the audio device can come back */
1088 mutex_lock(&vgasr_mutex);
1089 list_for_each_entry(client, &vgasr_priv.clients, list) {
1090 if (PCI_SLOT(client->pdev->devfn) == PCI_SLOT(pdev->devfn) &&
1091 client_is_vga(client)) {
1092 video_dev = &client->pdev->dev;
1093 break;
1094 }
1095 }
1096 mutex_unlock(&vgasr_mutex);
1097
1098 if (video_dev) {
1099 ret = pm_runtime_get_sync(video_dev);
1100 if (ret && ret != 1)
1101 return ret;
1102 }
1103 ret = dev->bus->pm->runtime_resume(dev);
1104
1105 /* put the reference for the gpu */
1106 if (video_dev) {
1107 pm_runtime_mark_last_busy(video_dev);
1108 pm_runtime_put_autosuspend(video_dev);
1109 }
1110 return ret;
1111}
1112
1113/**
1114 * vga_switcheroo_init_domain_pm_optimus_hdmi_audio() - helper for driver
1115 * power control
1116 * @dev: audio client device
1117 * @domain: power domain
1118 *
1119 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
1120 * When the audio device resumes, the GPU needs to be woken. This helper
1121 * augments the audio device's resume function to do that.
1122 *
1123 * Return: 0 on success, -EINVAL if no power management operations are
1124 * defined for this device.
1125 */
1126int
1127vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
1128 struct dev_pm_domain *domain)
1129{
1130 /* copy over all the bus versions */
1131 if (dev->bus && dev->bus->pm) {
1132 domain->ops = *dev->bus->pm;
1133 domain->ops.runtime_resume =
1134 vga_switcheroo_runtime_resume_hdmi_audio;
1135
1136 dev_pm_domain_set(dev, domain);
1137 return 0;
1138 }
1139 dev_pm_domain_set(dev, NULL);
1140 return -EINVAL;
1141}
1142EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);