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1/*
2 * Copyright (c) 2010 Red Hat Inc.
3 * Author : Dave Airlie <airlied@redhat.com>
4 *
5 *
6 * Licensed under GPLv2
7 *
8 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
9
10 Switcher interface - methods require for ATPX and DCM
11 - switchto - this throws the output MUX switch
12 - discrete_set_power - sets the power state for the discrete card
13
14 GPU driver interface
15 - set_gpu_state - this should do the equiv of s/r for the card
16 - this should *not* set the discrete power state
17 - switch_check - check if the device is in a position to switch now
18 */
19
20#include <linux/module.h>
21#include <linux/dmi.h>
22#include <linux/seq_file.h>
23#include <linux/uaccess.h>
24#include <linux/fs.h>
25#include <linux/debugfs.h>
26#include <linux/fb.h>
27
28#include <linux/pci.h>
29#include <linux/vga_switcheroo.h>
30
31struct vga_switcheroo_client {
32 struct pci_dev *pdev;
33 struct fb_info *fb_info;
34 int pwr_state;
35 void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state);
36 void (*reprobe)(struct pci_dev *pdev);
37 bool (*can_switch)(struct pci_dev *pdev);
38 int id;
39 bool active;
40};
41
42static DEFINE_MUTEX(vgasr_mutex);
43
44struct vgasr_priv {
45
46 bool active;
47 bool delayed_switch_active;
48 enum vga_switcheroo_client_id delayed_client_id;
49
50 struct dentry *debugfs_root;
51 struct dentry *switch_file;
52
53 int registered_clients;
54 struct vga_switcheroo_client clients[VGA_SWITCHEROO_MAX_CLIENTS];
55
56 struct vga_switcheroo_handler *handler;
57};
58
59static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
60static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
61
62/* only one switcheroo per system */
63static struct vgasr_priv vgasr_priv;
64
65int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
66{
67 mutex_lock(&vgasr_mutex);
68 if (vgasr_priv.handler) {
69 mutex_unlock(&vgasr_mutex);
70 return -EINVAL;
71 }
72
73 vgasr_priv.handler = handler;
74 mutex_unlock(&vgasr_mutex);
75 return 0;
76}
77EXPORT_SYMBOL(vga_switcheroo_register_handler);
78
79void vga_switcheroo_unregister_handler(void)
80{
81 mutex_lock(&vgasr_mutex);
82 vgasr_priv.handler = NULL;
83 mutex_unlock(&vgasr_mutex);
84}
85EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
86
87static void vga_switcheroo_enable(void)
88{
89 int i;
90 int ret;
91 /* call the handler to init */
92 vgasr_priv.handler->init();
93
94 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
95 ret = vgasr_priv.handler->get_client_id(vgasr_priv.clients[i].pdev);
96 if (ret < 0)
97 return;
98
99 vgasr_priv.clients[i].id = ret;
100 }
101 vga_switcheroo_debugfs_init(&vgasr_priv);
102 vgasr_priv.active = true;
103}
104
105int vga_switcheroo_register_client(struct pci_dev *pdev,
106 void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state),
107 void (*reprobe)(struct pci_dev *pdev),
108 bool (*can_switch)(struct pci_dev *pdev))
109{
110 int index;
111
112 mutex_lock(&vgasr_mutex);
113 /* don't do IGD vs DIS here */
114 if (vgasr_priv.registered_clients & 1)
115 index = 1;
116 else
117 index = 0;
118
119 vgasr_priv.clients[index].pwr_state = VGA_SWITCHEROO_ON;
120 vgasr_priv.clients[index].pdev = pdev;
121 vgasr_priv.clients[index].set_gpu_state = set_gpu_state;
122 vgasr_priv.clients[index].reprobe = reprobe;
123 vgasr_priv.clients[index].can_switch = can_switch;
124 vgasr_priv.clients[index].id = -1;
125 if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
126 vgasr_priv.clients[index].active = true;
127
128 vgasr_priv.registered_clients |= (1 << index);
129
130 /* if we get two clients + handler */
131 if (vgasr_priv.registered_clients == 0x3 && vgasr_priv.handler) {
132 printk(KERN_INFO "vga_switcheroo: enabled\n");
133 vga_switcheroo_enable();
134 }
135 mutex_unlock(&vgasr_mutex);
136 return 0;
137}
138EXPORT_SYMBOL(vga_switcheroo_register_client);
139
140void vga_switcheroo_unregister_client(struct pci_dev *pdev)
141{
142 int i;
143
144 mutex_lock(&vgasr_mutex);
145 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
146 if (vgasr_priv.clients[i].pdev == pdev) {
147 vgasr_priv.registered_clients &= ~(1 << i);
148 break;
149 }
150 }
151
152 printk(KERN_INFO "vga_switcheroo: disabled\n");
153 vga_switcheroo_debugfs_fini(&vgasr_priv);
154 vgasr_priv.active = false;
155 mutex_unlock(&vgasr_mutex);
156}
157EXPORT_SYMBOL(vga_switcheroo_unregister_client);
158
159void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
160 struct fb_info *info)
161{
162 int i;
163
164 mutex_lock(&vgasr_mutex);
165 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
166 if (vgasr_priv.clients[i].pdev == pdev) {
167 vgasr_priv.clients[i].fb_info = info;
168 break;
169 }
170 }
171 mutex_unlock(&vgasr_mutex);
172}
173EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
174
175static int vga_switcheroo_show(struct seq_file *m, void *v)
176{
177 int i;
178 mutex_lock(&vgasr_mutex);
179 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
180 seq_printf(m, "%d:%s:%c:%s:%s\n", i,
181 vgasr_priv.clients[i].id == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
182 vgasr_priv.clients[i].active ? '+' : ' ',
183 vgasr_priv.clients[i].pwr_state ? "Pwr" : "Off",
184 pci_name(vgasr_priv.clients[i].pdev));
185 }
186 mutex_unlock(&vgasr_mutex);
187 return 0;
188}
189
190static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
191{
192 return single_open(file, vga_switcheroo_show, NULL);
193}
194
195static int vga_switchon(struct vga_switcheroo_client *client)
196{
197 if (vgasr_priv.handler->power_state)
198 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
199 /* call the driver callback to turn on device */
200 client->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
201 client->pwr_state = VGA_SWITCHEROO_ON;
202 return 0;
203}
204
205static int vga_switchoff(struct vga_switcheroo_client *client)
206{
207 /* call the driver callback to turn off device */
208 client->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
209 if (vgasr_priv.handler->power_state)
210 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
211 client->pwr_state = VGA_SWITCHEROO_OFF;
212 return 0;
213}
214
215/* stage one happens before delay */
216static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
217{
218 int i;
219 struct vga_switcheroo_client *active = NULL;
220
221 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
222 if (vgasr_priv.clients[i].active == true) {
223 active = &vgasr_priv.clients[i];
224 break;
225 }
226 }
227 if (!active)
228 return 0;
229
230 if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
231 vga_switchon(new_client);
232
233 /* swap shadow resource to denote boot VGA device has changed so X starts on new device */
234 active->pdev->resource[PCI_ROM_RESOURCE].flags &= ~IORESOURCE_ROM_SHADOW;
235 new_client->pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
236 return 0;
237}
238
239/* post delay */
240static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
241{
242 int ret;
243 int i;
244 struct vga_switcheroo_client *active = NULL;
245
246 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
247 if (vgasr_priv.clients[i].active == true) {
248 active = &vgasr_priv.clients[i];
249 break;
250 }
251 }
252 if (!active)
253 return 0;
254
255 active->active = false;
256
257 if (new_client->fb_info) {
258 struct fb_event event;
259 event.info = new_client->fb_info;
260 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
261 }
262
263 ret = vgasr_priv.handler->switchto(new_client->id);
264 if (ret)
265 return ret;
266
267 if (new_client->reprobe)
268 new_client->reprobe(new_client->pdev);
269
270 if (active->pwr_state == VGA_SWITCHEROO_ON)
271 vga_switchoff(active);
272
273 new_client->active = true;
274 return 0;
275}
276
277static ssize_t
278vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
279 size_t cnt, loff_t *ppos)
280{
281 char usercmd[64];
282 const char *pdev_name;
283 int i, ret;
284 bool delay = false, can_switch;
285 bool just_mux = false;
286 int client_id = -1;
287 struct vga_switcheroo_client *client = NULL;
288
289 if (cnt > 63)
290 cnt = 63;
291
292 if (copy_from_user(usercmd, ubuf, cnt))
293 return -EFAULT;
294
295 mutex_lock(&vgasr_mutex);
296
297 if (!vgasr_priv.active) {
298 cnt = -EINVAL;
299 goto out;
300 }
301
302 /* pwr off the device not in use */
303 if (strncmp(usercmd, "OFF", 3) == 0) {
304 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
305 if (vgasr_priv.clients[i].active)
306 continue;
307 if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_ON)
308 vga_switchoff(&vgasr_priv.clients[i]);
309 }
310 goto out;
311 }
312 /* pwr on the device not in use */
313 if (strncmp(usercmd, "ON", 2) == 0) {
314 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
315 if (vgasr_priv.clients[i].active)
316 continue;
317 if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_OFF)
318 vga_switchon(&vgasr_priv.clients[i]);
319 }
320 goto out;
321 }
322
323 /* request a delayed switch - test can we switch now */
324 if (strncmp(usercmd, "DIGD", 4) == 0) {
325 client_id = VGA_SWITCHEROO_IGD;
326 delay = true;
327 }
328
329 if (strncmp(usercmd, "DDIS", 4) == 0) {
330 client_id = VGA_SWITCHEROO_DIS;
331 delay = true;
332 }
333
334 if (strncmp(usercmd, "IGD", 3) == 0)
335 client_id = VGA_SWITCHEROO_IGD;
336
337 if (strncmp(usercmd, "DIS", 3) == 0)
338 client_id = VGA_SWITCHEROO_DIS;
339
340 if (strncmp(usercmd, "MIGD", 4) == 0) {
341 just_mux = true;
342 client_id = VGA_SWITCHEROO_IGD;
343 }
344 if (strncmp(usercmd, "MDIS", 4) == 0) {
345 just_mux = true;
346 client_id = VGA_SWITCHEROO_DIS;
347 }
348
349 if (client_id == -1)
350 goto out;
351
352 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
353 if (vgasr_priv.clients[i].id == client_id) {
354 client = &vgasr_priv.clients[i];
355 break;
356 }
357 }
358
359 vgasr_priv.delayed_switch_active = false;
360
361 if (just_mux) {
362 ret = vgasr_priv.handler->switchto(client_id);
363 goto out;
364 }
365
366 if (client->active == true)
367 goto out;
368
369 /* okay we want a switch - test if devices are willing to switch */
370 can_switch = true;
371 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
372 can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
373 if (can_switch == false) {
374 printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
375 break;
376 }
377 }
378
379 if (can_switch == false && delay == false)
380 goto out;
381
382 if (can_switch == true) {
383 pdev_name = pci_name(client->pdev);
384 ret = vga_switchto_stage1(client);
385 if (ret)
386 printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
387
388 ret = vga_switchto_stage2(client);
389 if (ret)
390 printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
391
392 } else {
393 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
394 vgasr_priv.delayed_switch_active = true;
395 vgasr_priv.delayed_client_id = client_id;
396
397 ret = vga_switchto_stage1(client);
398 if (ret)
399 printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
400 }
401
402out:
403 mutex_unlock(&vgasr_mutex);
404 return cnt;
405}
406
407static const struct file_operations vga_switcheroo_debugfs_fops = {
408 .owner = THIS_MODULE,
409 .open = vga_switcheroo_debugfs_open,
410 .write = vga_switcheroo_debugfs_write,
411 .read = seq_read,
412 .llseek = seq_lseek,
413 .release = single_release,
414};
415
416static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
417{
418 if (priv->switch_file) {
419 debugfs_remove(priv->switch_file);
420 priv->switch_file = NULL;
421 }
422 if (priv->debugfs_root) {
423 debugfs_remove(priv->debugfs_root);
424 priv->debugfs_root = NULL;
425 }
426}
427
428static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
429{
430 /* already initialised */
431 if (priv->debugfs_root)
432 return 0;
433 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
434
435 if (!priv->debugfs_root) {
436 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
437 goto fail;
438 }
439
440 priv->switch_file = debugfs_create_file("switch", 0644,
441 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
442 if (!priv->switch_file) {
443 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
444 goto fail;
445 }
446 return 0;
447fail:
448 vga_switcheroo_debugfs_fini(priv);
449 return -1;
450}
451
452int vga_switcheroo_process_delayed_switch(void)
453{
454 struct vga_switcheroo_client *client = NULL;
455 const char *pdev_name;
456 bool can_switch = true;
457 int i;
458 int ret;
459 int err = -EINVAL;
460
461 mutex_lock(&vgasr_mutex);
462 if (!vgasr_priv.delayed_switch_active)
463 goto err;
464
465 printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
466
467 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
468 if (vgasr_priv.clients[i].id == vgasr_priv.delayed_client_id)
469 client = &vgasr_priv.clients[i];
470 can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
471 if (can_switch == false) {
472 printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
473 break;
474 }
475 }
476
477 if (can_switch == false || client == NULL)
478 goto err;
479
480 pdev_name = pci_name(client->pdev);
481 ret = vga_switchto_stage2(client);
482 if (ret)
483 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
484
485 vgasr_priv.delayed_switch_active = false;
486 err = 0;
487err:
488 mutex_unlock(&vgasr_mutex);
489 return err;
490}
491EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
492
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 if manual power control is used.
96 * For driver power control, call vga_switcheroo_pwr_state().
97 * @ops: client callbacks
98 * @id: client identifier. Determining the id requires the handler,
99 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
100 * and later given their true id in vga_switcheroo_enable()
101 * @active: whether the outputs are currently switched to this client
102 * @driver_power_control: whether power state is controlled by the driver's
103 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
104 * interface is a no-op so as not to interfere with runtime pm
105 * @list: client list
106 *
107 * Registered client. A client can be either a GPU or an audio device on a GPU.
108 * For audio clients, the @fb_info and @active members 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(
218 const struct vga_switcheroo_handler *handler,
219 enum vga_switcheroo_handler_flags_t handler_flags)
220{
221 mutex_lock(&vgasr_mutex);
222 if (vgasr_priv.handler) {
223 mutex_unlock(&vgasr_mutex);
224 return -EINVAL;
225 }
226
227 vgasr_priv.handler = handler;
228 vgasr_priv.handler_flags = handler_flags;
229 if (vga_switcheroo_ready()) {
230 pr_info("enabled\n");
231 vga_switcheroo_enable();
232 }
233 mutex_unlock(&vgasr_mutex);
234 return 0;
235}
236EXPORT_SYMBOL(vga_switcheroo_register_handler);
237
238/**
239 * vga_switcheroo_unregister_handler() - unregister handler
240 *
241 * Unregister handler. Disable vga_switcheroo.
242 */
243void vga_switcheroo_unregister_handler(void)
244{
245 mutex_lock(&vgasr_mutex);
246 mutex_lock(&vgasr_priv.mux_hw_lock);
247 vgasr_priv.handler_flags = 0;
248 vgasr_priv.handler = NULL;
249 if (vgasr_priv.active) {
250 pr_info("disabled\n");
251 vga_switcheroo_debugfs_fini(&vgasr_priv);
252 vgasr_priv.active = false;
253 }
254 mutex_unlock(&vgasr_priv.mux_hw_lock);
255 mutex_unlock(&vgasr_mutex);
256}
257EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
258
259/**
260 * vga_switcheroo_handler_flags() - obtain handler flags
261 *
262 * Helper for clients to obtain the handler flags bitmask.
263 *
264 * Return: Handler flags. A value of 0 means that no handler is registered
265 * or that the handler has no special capabilities.
266 */
267enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void)
268{
269 return vgasr_priv.handler_flags;
270}
271EXPORT_SYMBOL(vga_switcheroo_handler_flags);
272
273static int register_client(struct pci_dev *pdev,
274 const struct vga_switcheroo_client_ops *ops,
275 enum vga_switcheroo_client_id id, bool active,
276 bool driver_power_control)
277{
278 struct vga_switcheroo_client *client;
279
280 client = kzalloc(sizeof(*client), GFP_KERNEL);
281 if (!client)
282 return -ENOMEM;
283
284 client->pwr_state = VGA_SWITCHEROO_ON;
285 client->pdev = pdev;
286 client->ops = ops;
287 client->id = id;
288 client->active = active;
289 client->driver_power_control = driver_power_control;
290
291 mutex_lock(&vgasr_mutex);
292 list_add_tail(&client->list, &vgasr_priv.clients);
293 if (client_is_vga(client))
294 vgasr_priv.registered_clients++;
295
296 if (vga_switcheroo_ready()) {
297 pr_info("enabled\n");
298 vga_switcheroo_enable();
299 }
300 mutex_unlock(&vgasr_mutex);
301 return 0;
302}
303
304/**
305 * vga_switcheroo_register_client - register vga client
306 * @pdev: client pci device
307 * @ops: client callbacks
308 * @driver_power_control: whether power state is controlled by the driver's
309 * runtime pm
310 *
311 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
312 * handler have already registered. The power state of the client is assumed
313 * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called
314 * to ensure that all prerequisites are met.
315 *
316 * Return: 0 on success, -ENOMEM on memory allocation error.
317 */
318int vga_switcheroo_register_client(struct pci_dev *pdev,
319 const struct vga_switcheroo_client_ops *ops,
320 bool driver_power_control)
321{
322 return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID,
323 pdev == vga_default_device(),
324 driver_power_control);
325}
326EXPORT_SYMBOL(vga_switcheroo_register_client);
327
328/**
329 * vga_switcheroo_register_audio_client - register audio client
330 * @pdev: client pci device
331 * @ops: client callbacks
332 * @id: client identifier
333 *
334 * Register audio client (audio device on a GPU). The client is assumed
335 * to use runtime PM. Beforehand, vga_switcheroo_client_probe_defer()
336 * shall be called to ensure that all prerequisites are met.
337 *
338 * Return: 0 on success, -ENOMEM on memory allocation error.
339 */
340int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
341 const struct vga_switcheroo_client_ops *ops,
342 enum vga_switcheroo_client_id id)
343{
344 return register_client(pdev, ops, id | ID_BIT_AUDIO, false, true);
345}
346EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
347
348static struct vga_switcheroo_client *
349find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
350{
351 struct vga_switcheroo_client *client;
352
353 list_for_each_entry(client, head, list)
354 if (client->pdev == pdev)
355 return client;
356 return NULL;
357}
358
359static struct vga_switcheroo_client *
360find_client_from_id(struct list_head *head,
361 enum vga_switcheroo_client_id client_id)
362{
363 struct vga_switcheroo_client *client;
364
365 list_for_each_entry(client, head, list)
366 if (client->id == client_id)
367 return client;
368 return NULL;
369}
370
371static struct vga_switcheroo_client *
372find_active_client(struct list_head *head)
373{
374 struct vga_switcheroo_client *client;
375
376 list_for_each_entry(client, head, list)
377 if (client->active)
378 return client;
379 return NULL;
380}
381
382/**
383 * vga_switcheroo_client_probe_defer() - whether to defer probing a given client
384 * @pdev: client pci device
385 *
386 * Determine whether any prerequisites are not fulfilled to probe a given
387 * client. Drivers shall invoke this early on in their ->probe callback
388 * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
389 * register the client ere thou hast called this.
390 *
391 * Return: %true if probing should be deferred, otherwise %false.
392 */
393bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
394{
395 if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
396 /*
397 * apple-gmux is needed on pre-retina MacBook Pro
398 * to probe the panel if pdev is the inactive GPU.
399 */
400 if (apple_gmux_present() && pdev != vga_default_device() &&
401 !vgasr_priv.handler_flags)
402 return true;
403 }
404
405 return false;
406}
407EXPORT_SYMBOL(vga_switcheroo_client_probe_defer);
408
409static enum vga_switcheroo_state
410vga_switcheroo_pwr_state(struct vga_switcheroo_client *client)
411{
412 if (client->driver_power_control)
413 if (pm_runtime_enabled(&client->pdev->dev) &&
414 pm_runtime_active(&client->pdev->dev))
415 return VGA_SWITCHEROO_ON;
416 else
417 return VGA_SWITCHEROO_OFF;
418 else
419 return client->pwr_state;
420}
421
422/**
423 * vga_switcheroo_get_client_state() - obtain power state of a given client
424 * @pdev: client pci device
425 *
426 * Obtain power state of a given client as seen from vga_switcheroo.
427 * The function is only called from hda_intel.c.
428 *
429 * Return: Power state.
430 */
431enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev)
432{
433 struct vga_switcheroo_client *client;
434 enum vga_switcheroo_state ret;
435
436 mutex_lock(&vgasr_mutex);
437 client = find_client_from_pci(&vgasr_priv.clients, pdev);
438 if (!client)
439 ret = VGA_SWITCHEROO_NOT_FOUND;
440 else
441 ret = vga_switcheroo_pwr_state(client);
442 mutex_unlock(&vgasr_mutex);
443 return ret;
444}
445EXPORT_SYMBOL(vga_switcheroo_get_client_state);
446
447/**
448 * vga_switcheroo_unregister_client() - unregister client
449 * @pdev: client pci device
450 *
451 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
452 */
453void vga_switcheroo_unregister_client(struct pci_dev *pdev)
454{
455 struct vga_switcheroo_client *client;
456
457 mutex_lock(&vgasr_mutex);
458 client = find_client_from_pci(&vgasr_priv.clients, pdev);
459 if (client) {
460 if (client_is_vga(client))
461 vgasr_priv.registered_clients--;
462 list_del(&client->list);
463 kfree(client);
464 }
465 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
466 pr_info("disabled\n");
467 vga_switcheroo_debugfs_fini(&vgasr_priv);
468 vgasr_priv.active = false;
469 }
470 mutex_unlock(&vgasr_mutex);
471}
472EXPORT_SYMBOL(vga_switcheroo_unregister_client);
473
474/**
475 * vga_switcheroo_client_fb_set() - set framebuffer of a given client
476 * @pdev: client pci device
477 * @info: framebuffer
478 *
479 * Set framebuffer of a given client. The console will be remapped to this
480 * on switching.
481 */
482void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
483 struct fb_info *info)
484{
485 struct vga_switcheroo_client *client;
486
487 mutex_lock(&vgasr_mutex);
488 client = find_client_from_pci(&vgasr_priv.clients, pdev);
489 if (client)
490 client->fb_info = info;
491 mutex_unlock(&vgasr_mutex);
492}
493EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
494
495/**
496 * vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client
497 * @pdev: client pci device
498 *
499 * Temporarily switch DDC lines to the client identified by @pdev
500 * (but leave the outputs otherwise switched to where they are).
501 * This allows the inactive client to probe EDID. The DDC lines must
502 * afterwards be switched back by calling vga_switcheroo_unlock_ddc(),
503 * even if this function returns an error.
504 *
505 * Return: Previous DDC owner on success or a negative int on error.
506 * Specifically, %-ENODEV if no handler has registered or if the handler
507 * does not support switching the DDC lines. Also, a negative value
508 * returned by the handler is propagated back to the caller.
509 * The return value has merely an informational purpose for any caller
510 * which might be interested in it. It is acceptable to ignore the return
511 * value and simply rely on the result of the subsequent EDID probe,
512 * which will be %NULL if DDC switching failed.
513 */
514int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
515{
516 enum vga_switcheroo_client_id id;
517
518 mutex_lock(&vgasr_priv.mux_hw_lock);
519 if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) {
520 vgasr_priv.old_ddc_owner = -ENODEV;
521 return -ENODEV;
522 }
523
524 id = vgasr_priv.handler->get_client_id(pdev);
525 vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id);
526 return vgasr_priv.old_ddc_owner;
527}
528EXPORT_SYMBOL(vga_switcheroo_lock_ddc);
529
530/**
531 * vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner
532 * @pdev: client pci device
533 *
534 * Switch DDC lines back to the previous owner after calling
535 * vga_switcheroo_lock_ddc(). This must be called even if
536 * vga_switcheroo_lock_ddc() returned an error.
537 *
538 * Return: Previous DDC owner on success (i.e. the client identifier of @pdev)
539 * or a negative int on error.
540 * Specifically, %-ENODEV if no handler has registered or if the handler
541 * does not support switching the DDC lines. Also, a negative value
542 * returned by the handler is propagated back to the caller.
543 * Finally, invoking this function without calling vga_switcheroo_lock_ddc()
544 * first is not allowed and will result in %-EINVAL.
545 */
546int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
547{
548 enum vga_switcheroo_client_id id;
549 int ret = vgasr_priv.old_ddc_owner;
550
551 if (WARN_ON_ONCE(!mutex_is_locked(&vgasr_priv.mux_hw_lock)))
552 return -EINVAL;
553
554 if (vgasr_priv.old_ddc_owner >= 0) {
555 id = vgasr_priv.handler->get_client_id(pdev);
556 if (vgasr_priv.old_ddc_owner != id)
557 ret = vgasr_priv.handler->switch_ddc(
558 vgasr_priv.old_ddc_owner);
559 }
560 mutex_unlock(&vgasr_priv.mux_hw_lock);
561 return ret;
562}
563EXPORT_SYMBOL(vga_switcheroo_unlock_ddc);
564
565/**
566 * DOC: Manual switching and manual power control
567 *
568 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
569 * can be read to retrieve the current vga_switcheroo state and commands
570 * can be written to it to change the state. The file appears as soon as
571 * two GPU drivers and one handler have registered with vga_switcheroo.
572 * The following commands are understood:
573 *
574 * * OFF: Power off the device not in use.
575 * * ON: Power on the device not in use.
576 * * IGD: Switch to the integrated graphics device.
577 * Power on the integrated GPU if necessary, power off the discrete GPU.
578 * Prerequisite is that no user space processes (e.g. Xorg, alsactl)
579 * have opened device files of the GPUs or the audio client. If the
580 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
581 * and /dev/snd/controlC1 to identify processes blocking the switch.
582 * * DIS: Switch to the discrete graphics device.
583 * * DIGD: Delayed switch to the integrated graphics device.
584 * This will perform the switch once the last user space process has
585 * closed the device files of the GPUs and the audio client.
586 * * DDIS: Delayed switch to the discrete graphics device.
587 * * MIGD: Mux-only switch to the integrated graphics device.
588 * Does not remap console or change the power state of either gpu.
589 * If the integrated GPU is currently off, the screen will turn black.
590 * If it is on, the screen will show whatever happens to be in VRAM.
591 * Either way, the user has to blindly enter the command to switch back.
592 * * MDIS: Mux-only switch to the discrete graphics device.
593 *
594 * For GPUs whose power state is controlled by the driver's runtime pm,
595 * the ON and OFF commands are a no-op (see next section).
596 *
597 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
598 * should not be used.
599 */
600
601static int vga_switcheroo_show(struct seq_file *m, void *v)
602{
603 struct vga_switcheroo_client *client;
604 int i = 0;
605
606 mutex_lock(&vgasr_mutex);
607 list_for_each_entry(client, &vgasr_priv.clients, list) {
608 seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
609 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" :
610 "IGD",
611 client_is_vga(client) ? "" : "-Audio",
612 client->active ? '+' : ' ',
613 client->driver_power_control ? "Dyn" : "",
614 vga_switcheroo_pwr_state(client) ? "Pwr" : "Off",
615 pci_name(client->pdev));
616 i++;
617 }
618 mutex_unlock(&vgasr_mutex);
619 return 0;
620}
621
622static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
623{
624 return single_open(file, vga_switcheroo_show, NULL);
625}
626
627static int vga_switchon(struct vga_switcheroo_client *client)
628{
629 if (client->driver_power_control)
630 return 0;
631 if (vgasr_priv.handler->power_state)
632 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
633 /* call the driver callback to turn on device */
634 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
635 client->pwr_state = VGA_SWITCHEROO_ON;
636 return 0;
637}
638
639static int vga_switchoff(struct vga_switcheroo_client *client)
640{
641 if (client->driver_power_control)
642 return 0;
643 /* call the driver callback to turn off device */
644 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
645 if (vgasr_priv.handler->power_state)
646 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
647 client->pwr_state = VGA_SWITCHEROO_OFF;
648 return 0;
649}
650
651static void set_audio_state(enum vga_switcheroo_client_id id,
652 enum vga_switcheroo_state state)
653{
654 struct vga_switcheroo_client *client;
655
656 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
657 if (client)
658 client->ops->set_gpu_state(client->pdev, state);
659}
660
661/* stage one happens before delay */
662static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
663{
664 struct vga_switcheroo_client *active;
665
666 active = find_active_client(&vgasr_priv.clients);
667 if (!active)
668 return 0;
669
670 if (vga_switcheroo_pwr_state(new_client) == VGA_SWITCHEROO_OFF)
671 vga_switchon(new_client);
672
673 vga_set_default_device(new_client->pdev);
674 return 0;
675}
676
677/* post delay */
678static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
679{
680 int ret;
681 struct vga_switcheroo_client *active;
682
683 active = find_active_client(&vgasr_priv.clients);
684 if (!active)
685 return 0;
686
687 active->active = false;
688
689 /* let HDA controller autosuspend if GPU uses driver power control */
690 if (!active->driver_power_control)
691 set_audio_state(active->id, VGA_SWITCHEROO_OFF);
692
693 if (new_client->fb_info) {
694 struct fb_event event;
695
696 console_lock();
697 event.info = new_client->fb_info;
698 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
699 console_unlock();
700 }
701
702 mutex_lock(&vgasr_priv.mux_hw_lock);
703 ret = vgasr_priv.handler->switchto(new_client->id);
704 mutex_unlock(&vgasr_priv.mux_hw_lock);
705 if (ret)
706 return ret;
707
708 if (new_client->ops->reprobe)
709 new_client->ops->reprobe(new_client->pdev);
710
711 if (vga_switcheroo_pwr_state(active) == VGA_SWITCHEROO_ON)
712 vga_switchoff(active);
713
714 /* let HDA controller autoresume if GPU uses driver power control */
715 if (!new_client->driver_power_control)
716 set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
717
718 new_client->active = true;
719 return 0;
720}
721
722static bool check_can_switch(void)
723{
724 struct vga_switcheroo_client *client;
725
726 list_for_each_entry(client, &vgasr_priv.clients, list) {
727 if (!client->ops->can_switch(client->pdev)) {
728 pr_err("client %x refused switch\n", client->id);
729 return false;
730 }
731 }
732 return true;
733}
734
735static ssize_t
736vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
737 size_t cnt, loff_t *ppos)
738{
739 char usercmd[64];
740 int ret;
741 bool delay = false, can_switch;
742 bool just_mux = false;
743 enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID;
744 struct vga_switcheroo_client *client = NULL;
745
746 if (cnt > 63)
747 cnt = 63;
748
749 if (copy_from_user(usercmd, ubuf, cnt))
750 return -EFAULT;
751
752 mutex_lock(&vgasr_mutex);
753
754 if (!vgasr_priv.active) {
755 cnt = -EINVAL;
756 goto out;
757 }
758
759 /* pwr off the device not in use */
760 if (strncmp(usercmd, "OFF", 3) == 0) {
761 list_for_each_entry(client, &vgasr_priv.clients, list) {
762 if (client->active || client_is_audio(client))
763 continue;
764 if (client->driver_power_control)
765 continue;
766 set_audio_state(client->id, VGA_SWITCHEROO_OFF);
767 if (client->pwr_state == VGA_SWITCHEROO_ON)
768 vga_switchoff(client);
769 }
770 goto out;
771 }
772 /* pwr on the device not in use */
773 if (strncmp(usercmd, "ON", 2) == 0) {
774 list_for_each_entry(client, &vgasr_priv.clients, list) {
775 if (client->active || client_is_audio(client))
776 continue;
777 if (client->driver_power_control)
778 continue;
779 if (client->pwr_state == VGA_SWITCHEROO_OFF)
780 vga_switchon(client);
781 set_audio_state(client->id, VGA_SWITCHEROO_ON);
782 }
783 goto out;
784 }
785
786 /* request a delayed switch - test can we switch now */
787 if (strncmp(usercmd, "DIGD", 4) == 0) {
788 client_id = VGA_SWITCHEROO_IGD;
789 delay = true;
790 }
791
792 if (strncmp(usercmd, "DDIS", 4) == 0) {
793 client_id = VGA_SWITCHEROO_DIS;
794 delay = true;
795 }
796
797 if (strncmp(usercmd, "IGD", 3) == 0)
798 client_id = VGA_SWITCHEROO_IGD;
799
800 if (strncmp(usercmd, "DIS", 3) == 0)
801 client_id = VGA_SWITCHEROO_DIS;
802
803 if (strncmp(usercmd, "MIGD", 4) == 0) {
804 just_mux = true;
805 client_id = VGA_SWITCHEROO_IGD;
806 }
807 if (strncmp(usercmd, "MDIS", 4) == 0) {
808 just_mux = true;
809 client_id = VGA_SWITCHEROO_DIS;
810 }
811
812 if (client_id == VGA_SWITCHEROO_UNKNOWN_ID)
813 goto out;
814 client = find_client_from_id(&vgasr_priv.clients, client_id);
815 if (!client)
816 goto out;
817
818 vgasr_priv.delayed_switch_active = false;
819
820 if (just_mux) {
821 mutex_lock(&vgasr_priv.mux_hw_lock);
822 ret = vgasr_priv.handler->switchto(client_id);
823 mutex_unlock(&vgasr_priv.mux_hw_lock);
824 goto out;
825 }
826
827 if (client->active)
828 goto out;
829
830 /* okay we want a switch - test if devices are willing to switch */
831 can_switch = check_can_switch();
832
833 if (can_switch == false && delay == false)
834 goto out;
835
836 if (can_switch) {
837 ret = vga_switchto_stage1(client);
838 if (ret)
839 pr_err("switching failed stage 1 %d\n", ret);
840
841 ret = vga_switchto_stage2(client);
842 if (ret)
843 pr_err("switching failed stage 2 %d\n", ret);
844
845 } else {
846 pr_info("setting delayed switch to client %d\n", client->id);
847 vgasr_priv.delayed_switch_active = true;
848 vgasr_priv.delayed_client_id = client_id;
849
850 ret = vga_switchto_stage1(client);
851 if (ret)
852 pr_err("delayed switching stage 1 failed %d\n", ret);
853 }
854
855out:
856 mutex_unlock(&vgasr_mutex);
857 return cnt;
858}
859
860static const struct file_operations vga_switcheroo_debugfs_fops = {
861 .owner = THIS_MODULE,
862 .open = vga_switcheroo_debugfs_open,
863 .write = vga_switcheroo_debugfs_write,
864 .read = seq_read,
865 .llseek = seq_lseek,
866 .release = single_release,
867};
868
869static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
870{
871 debugfs_remove(priv->switch_file);
872 priv->switch_file = NULL;
873
874 debugfs_remove(priv->debugfs_root);
875 priv->debugfs_root = NULL;
876}
877
878static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
879{
880 static const char mp[] = "/sys/kernel/debug";
881
882 /* already initialised */
883 if (priv->debugfs_root)
884 return 0;
885 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
886
887 if (!priv->debugfs_root) {
888 pr_err("Cannot create %s/vgaswitcheroo\n", mp);
889 goto fail;
890 }
891
892 priv->switch_file = debugfs_create_file("switch", 0644,
893 priv->debugfs_root, NULL,
894 &vga_switcheroo_debugfs_fops);
895 if (!priv->switch_file) {
896 pr_err("cannot create %s/vgaswitcheroo/switch\n", mp);
897 goto fail;
898 }
899 return 0;
900fail:
901 vga_switcheroo_debugfs_fini(priv);
902 return -1;
903}
904
905/**
906 * vga_switcheroo_process_delayed_switch() - helper for delayed switching
907 *
908 * Process a delayed switch if one is pending. DRM drivers should call this
909 * from their ->lastclose callback.
910 *
911 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
912 * has unregistered in the meantime or if there are other clients blocking the
913 * switch. If the actual switch fails, an error is reported and 0 is returned.
914 */
915int vga_switcheroo_process_delayed_switch(void)
916{
917 struct vga_switcheroo_client *client;
918 int ret;
919 int err = -EINVAL;
920
921 mutex_lock(&vgasr_mutex);
922 if (!vgasr_priv.delayed_switch_active)
923 goto err;
924
925 pr_info("processing delayed switch to %d\n",
926 vgasr_priv.delayed_client_id);
927
928 client = find_client_from_id(&vgasr_priv.clients,
929 vgasr_priv.delayed_client_id);
930 if (!client || !check_can_switch())
931 goto err;
932
933 ret = vga_switchto_stage2(client);
934 if (ret)
935 pr_err("delayed switching failed stage 2 %d\n", ret);
936
937 vgasr_priv.delayed_switch_active = false;
938 err = 0;
939err:
940 mutex_unlock(&vgasr_mutex);
941 return err;
942}
943EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
944
945/**
946 * DOC: Driver power control
947 *
948 * In this mode of use, the discrete GPU automatically powers up and down at
949 * the discretion of the driver's runtime pm. On muxed machines, the user may
950 * still influence the muxer state by way of the debugfs interface, however
951 * the ON and OFF commands become a no-op for the discrete GPU.
952 *
953 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
954 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
955 * command line disables it.
956 *
957 * After the GPU has been suspended, the handler needs to be called to cut
958 * power to the GPU. Likewise it needs to reinstate power before the GPU
959 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
960 * which augments the GPU's suspend/resume functions by the requisite
961 * calls to the handler.
962 *
963 * When the audio device resumes, the GPU needs to be woken. This is achieved
964 * by a PCI quirk which calls device_link_add() to declare a dependency on the
965 * GPU. That way, the GPU is kept awake whenever and as long as the audio
966 * device is in use.
967 *
968 * On muxed machines, if the mux is initially switched to the discrete GPU,
969 * the user ends up with a black screen when the GPU powers down after boot.
970 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
971 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
972 */
973
974static void vga_switcheroo_power_switch(struct pci_dev *pdev,
975 enum vga_switcheroo_state state)
976{
977 struct vga_switcheroo_client *client;
978
979 if (!vgasr_priv.handler->power_state)
980 return;
981
982 client = find_client_from_pci(&vgasr_priv.clients, pdev);
983 if (!client)
984 return;
985
986 if (!client->driver_power_control)
987 return;
988
989 vgasr_priv.handler->power_state(client->id, state);
990}
991
992/* switcheroo power domain */
993static int vga_switcheroo_runtime_suspend(struct device *dev)
994{
995 struct pci_dev *pdev = to_pci_dev(dev);
996 int ret;
997
998 ret = dev->bus->pm->runtime_suspend(dev);
999 if (ret)
1000 return ret;
1001 mutex_lock(&vgasr_mutex);
1002 if (vgasr_priv.handler->switchto) {
1003 mutex_lock(&vgasr_priv.mux_hw_lock);
1004 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
1005 mutex_unlock(&vgasr_priv.mux_hw_lock);
1006 }
1007 pci_bus_set_current_state(pdev->bus, PCI_D3cold);
1008 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
1009 mutex_unlock(&vgasr_mutex);
1010 return 0;
1011}
1012
1013static int vga_switcheroo_runtime_resume(struct device *dev)
1014{
1015 struct pci_dev *pdev = to_pci_dev(dev);
1016 int ret;
1017
1018 mutex_lock(&vgasr_mutex);
1019 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
1020 mutex_unlock(&vgasr_mutex);
1021 pci_wakeup_bus(pdev->bus);
1022 ret = dev->bus->pm->runtime_resume(dev);
1023 if (ret)
1024 return ret;
1025
1026 return 0;
1027}
1028
1029/**
1030 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
1031 * @dev: vga client device
1032 * @domain: power domain
1033 *
1034 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
1035 * After the GPU has been suspended, the handler needs to be called to cut
1036 * power to the GPU. Likewise it needs to reinstate power before the GPU
1037 * can resume. To this end, this helper augments the suspend/resume functions
1038 * by the requisite calls to the handler. It needs only be called on platforms
1039 * where the power switch is separate to the device being powered down.
1040 */
1041int vga_switcheroo_init_domain_pm_ops(struct device *dev,
1042 struct dev_pm_domain *domain)
1043{
1044 /* copy over all the bus versions */
1045 if (dev->bus && dev->bus->pm) {
1046 domain->ops = *dev->bus->pm;
1047 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
1048 domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
1049
1050 dev_pm_domain_set(dev, domain);
1051 return 0;
1052 }
1053 dev_pm_domain_set(dev, NULL);
1054 return -EINVAL;
1055}
1056EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
1057
1058void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
1059{
1060 dev_pm_domain_set(dev, NULL);
1061}
1062EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);