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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  video.c - ACPI Video Driver
   4 *
   5 *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
   6 *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
   7 *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
   8 */
   9
  10#define pr_fmt(fmt) "ACPI: video: " fmt
  11
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/init.h>
  15#include <linux/types.h>
  16#include <linux/list.h>
  17#include <linux/mutex.h>
  18#include <linux/input.h>
  19#include <linux/backlight.h>
  20#include <linux/thermal.h>
  21#include <linux/sort.h>
  22#include <linux/pci.h>
  23#include <linux/pci_ids.h>
  24#include <linux/slab.h>
  25#include <linux/dmi.h>
  26#include <linux/suspend.h>
  27#include <linux/acpi.h>
  28#include <acpi/video.h>
  29#include <linux/uaccess.h>
  30
  31#define ACPI_VIDEO_BUS_NAME		"Video Bus"
  32#define ACPI_VIDEO_DEVICE_NAME		"Video Device"
  33
  34#define MAX_NAME_LEN	20
  35
  36MODULE_AUTHOR("Bruno Ducrot");
  37MODULE_DESCRIPTION("ACPI Video Driver");
  38MODULE_LICENSE("GPL");
  39
  40static bool brightness_switch_enabled = true;
  41module_param(brightness_switch_enabled, bool, 0644);
  42
  43/*
  44 * By default, we don't allow duplicate ACPI video bus devices
  45 * under the same VGA controller
  46 */
  47static bool allow_duplicates;
  48module_param(allow_duplicates, bool, 0644);
  49
  50#define REPORT_OUTPUT_KEY_EVENTS		0x01
  51#define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
  52static int report_key_events = -1;
  53module_param(report_key_events, int, 0644);
  54MODULE_PARM_DESC(report_key_events,
  55	"0: none, 1: output changes, 2: brightness changes, 3: all");
  56
  57static int hw_changes_brightness = -1;
  58module_param(hw_changes_brightness, int, 0644);
  59MODULE_PARM_DESC(hw_changes_brightness,
  60	"Set this to 1 on buggy hw which changes the brightness itself when "
  61	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
  62
  63/*
  64 * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
  65 * assumed even if not actually set.
  66 */
  67static bool device_id_scheme = false;
  68module_param(device_id_scheme, bool, 0444);
  69
  70static int only_lcd = -1;
  71module_param(only_lcd, int, 0444);
  72
  73static int register_backlight_delay;
  74module_param(register_backlight_delay, int, 0444);
  75MODULE_PARM_DESC(register_backlight_delay,
  76	"Delay in seconds before doing fallback (non GPU driver triggered) "
  77	"backlight registration, set to 0 to disable.");
  78
  79static bool may_report_brightness_keys;
  80static int register_count;
  81static DEFINE_MUTEX(register_count_mutex);
  82static DEFINE_MUTEX(video_list_lock);
  83static LIST_HEAD(video_bus_head);
  84static int acpi_video_bus_add(struct acpi_device *device);
  85static void acpi_video_bus_remove(struct acpi_device *device);
  86static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
  87static void acpi_video_bus_register_backlight_work(struct work_struct *ignored);
  88static DECLARE_DELAYED_WORK(video_bus_register_backlight_work,
  89			    acpi_video_bus_register_backlight_work);
  90
  91/*
  92 * Indices in the _BCL method response: the first two items are special,
  93 * the rest are all supported levels.
  94 *
  95 * See page 575 of the ACPI spec 3.0
  96 */
  97enum acpi_video_level_idx {
  98	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
  99	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
 100	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
 101};
 102
 103static const struct acpi_device_id video_device_ids[] = {
 104	{ACPI_VIDEO_HID, 0},
 105	{"", 0},
 106};
 107MODULE_DEVICE_TABLE(acpi, video_device_ids);
 108
 109static struct acpi_driver acpi_video_bus = {
 110	.name = "video",
 111	.class = ACPI_VIDEO_CLASS,
 112	.ids = video_device_ids,
 113	.ops = {
 114		.add = acpi_video_bus_add,
 115		.remove = acpi_video_bus_remove,
 116		.notify = acpi_video_bus_notify,
 117		},
 118};
 119
 120struct acpi_video_bus_flags {
 121	u8 multihead:1;		/* can switch video heads */
 122	u8 rom:1;		/* can retrieve a video rom */
 123	u8 post:1;		/* can configure the head to */
 124	u8 reserved:5;
 125};
 126
 127struct acpi_video_bus_cap {
 128	u8 _DOS:1;		/* Enable/Disable output switching */
 129	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
 130	u8 _ROM:1;		/* Get ROM Data */
 131	u8 _GPD:1;		/* Get POST Device */
 132	u8 _SPD:1;		/* Set POST Device */
 133	u8 _VPO:1;		/* Video POST Options */
 134	u8 reserved:2;
 135};
 136
 137struct acpi_video_device_attrib {
 138	u32 display_index:4;	/* A zero-based instance of the Display */
 139	u32 display_port_attachment:4;	/* This field differentiates the display type */
 140	u32 display_type:4;	/* Describe the specific type in use */
 141	u32 vendor_specific:4;	/* Chipset Vendor Specific */
 142	u32 bios_can_detect:1;	/* BIOS can detect the device */
 143	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
 144				   the VGA device. */
 145	u32 pipe_id:3;		/* For VGA multiple-head devices. */
 146	u32 reserved:10;	/* Must be 0 */
 147
 148	/*
 149	 * The device ID might not actually follow the scheme described by this
 150	 * struct acpi_video_device_attrib. If it does, then this bit
 151	 * device_id_scheme is set; otherwise, other fields should be ignored.
 152	 *
 153	 * (but also see the global flag device_id_scheme)
 154	 */
 155	u32 device_id_scheme:1;
 156};
 157
 158struct acpi_video_enumerated_device {
 159	union {
 160		u32 int_val;
 161		struct acpi_video_device_attrib attrib;
 162	} value;
 163	struct acpi_video_device *bind_info;
 164};
 165
 166struct acpi_video_bus {
 167	struct acpi_device *device;
 168	bool backlight_registered;
 169	u8 dos_setting;
 170	struct acpi_video_enumerated_device *attached_array;
 171	u8 attached_count;
 172	u8 child_count;
 173	struct acpi_video_bus_cap cap;
 174	struct acpi_video_bus_flags flags;
 175	struct list_head video_device_list;
 176	struct mutex device_list_lock;	/* protects video_device_list */
 177	struct list_head entry;
 178	struct input_dev *input;
 179	char phys[32];	/* for input device */
 180	struct notifier_block pm_nb;
 181};
 182
 183struct acpi_video_device_flags {
 184	u8 crt:1;
 185	u8 lcd:1;
 186	u8 tvout:1;
 187	u8 dvi:1;
 188	u8 bios:1;
 189	u8 unknown:1;
 190	u8 notify:1;
 191	u8 reserved:1;
 192};
 193
 194struct acpi_video_device_cap {
 195	u8 _ADR:1;		/* Return the unique ID */
 196	u8 _BCL:1;		/* Query list of brightness control levels supported */
 197	u8 _BCM:1;		/* Set the brightness level */
 198	u8 _BQC:1;		/* Get current brightness level */
 199	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
 200	u8 _DDC:1;		/* Return the EDID for this device */
 201};
 202
 203struct acpi_video_device {
 204	unsigned long device_id;
 205	struct acpi_video_device_flags flags;
 206	struct acpi_video_device_cap cap;
 207	struct list_head entry;
 208	struct delayed_work switch_brightness_work;
 209	int switch_brightness_event;
 210	struct acpi_video_bus *video;
 211	struct acpi_device *dev;
 212	struct acpi_video_device_brightness *brightness;
 213	struct backlight_device *backlight;
 214	struct thermal_cooling_device *cooling_dev;
 215};
 216
 217static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 218static void acpi_video_device_rebind(struct acpi_video_bus *video);
 219static void acpi_video_device_bind(struct acpi_video_bus *video,
 220				   struct acpi_video_device *device);
 221static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 222static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 223			int level);
 224static int acpi_video_device_lcd_get_level_current(
 225			struct acpi_video_device *device,
 226			unsigned long long *level, bool raw);
 227static int acpi_video_get_next_level(struct acpi_video_device *device,
 228				     u32 level_current, u32 event);
 229static void acpi_video_switch_brightness(struct work_struct *work);
 230
 231/* backlight device sysfs support */
 232static int acpi_video_get_brightness(struct backlight_device *bd)
 233{
 234	unsigned long long cur_level;
 235	int i;
 236	struct acpi_video_device *vd = bl_get_data(bd);
 237
 238	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 239		return -EINVAL;
 240	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
 241		if (vd->brightness->levels[i] == cur_level)
 242			return i - ACPI_VIDEO_FIRST_LEVEL;
 243	}
 244	return 0;
 245}
 246
 247static int acpi_video_set_brightness(struct backlight_device *bd)
 248{
 249	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
 250	struct acpi_video_device *vd = bl_get_data(bd);
 251
 252	cancel_delayed_work(&vd->switch_brightness_work);
 253	return acpi_video_device_lcd_set_level(vd,
 254				vd->brightness->levels[request_level]);
 255}
 256
 257static const struct backlight_ops acpi_backlight_ops = {
 258	.get_brightness = acpi_video_get_brightness,
 259	.update_status  = acpi_video_set_brightness,
 260};
 261
 262/* thermal cooling device callbacks */
 263static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
 264			       unsigned long *state)
 265{
 266	struct acpi_device *device = cooling_dev->devdata;
 267	struct acpi_video_device *video = acpi_driver_data(device);
 268
 269	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
 270	return 0;
 271}
 272
 273static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
 274			       unsigned long *state)
 275{
 276	struct acpi_device *device = cooling_dev->devdata;
 277	struct acpi_video_device *video = acpi_driver_data(device);
 278	unsigned long long level;
 279	int offset;
 280
 281	if (acpi_video_device_lcd_get_level_current(video, &level, false))
 282		return -EINVAL;
 283	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
 284	     offset++)
 285		if (level == video->brightness->levels[offset]) {
 286			*state = video->brightness->count - offset - 1;
 287			return 0;
 288		}
 289
 290	return -EINVAL;
 291}
 292
 293static int
 294video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 295{
 296	struct acpi_device *device = cooling_dev->devdata;
 297	struct acpi_video_device *video = acpi_driver_data(device);
 298	int level;
 299
 300	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
 301		return -EINVAL;
 302
 303	state = video->brightness->count - state;
 304	level = video->brightness->levels[state - 1];
 305	return acpi_video_device_lcd_set_level(video, level);
 306}
 307
 308static const struct thermal_cooling_device_ops video_cooling_ops = {
 309	.get_max_state = video_get_max_state,
 310	.get_cur_state = video_get_cur_state,
 311	.set_cur_state = video_set_cur_state,
 312};
 313
 314/*
 315 * --------------------------------------------------------------------------
 316 *                             Video Management
 317 * --------------------------------------------------------------------------
 318 */
 319
 320static int
 321acpi_video_device_lcd_query_levels(acpi_handle handle,
 322				   union acpi_object **levels)
 323{
 324	int status;
 325	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 326	union acpi_object *obj;
 327
 328
 329	*levels = NULL;
 330
 331	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
 332	if (ACPI_FAILURE(status))
 333		return status;
 334	obj = (union acpi_object *)buffer.pointer;
 335	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 336		acpi_handle_info(handle, "Invalid _BCL data\n");
 337		status = -EFAULT;
 338		goto err;
 339	}
 340
 341	*levels = obj;
 342
 343	return 0;
 344
 345err:
 346	kfree(buffer.pointer);
 347
 348	return status;
 349}
 350
 351static int
 352acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 353{
 354	int status;
 355	int state;
 356
 357	status = acpi_execute_simple_method(device->dev->handle,
 358					    "_BCM", level);
 359	if (ACPI_FAILURE(status)) {
 360		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
 361		return -EIO;
 362	}
 363
 364	device->brightness->curr = level;
 365	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
 366	     state++)
 367		if (level == device->brightness->levels[state]) {
 368			if (device->backlight)
 369				device->backlight->props.brightness =
 370					state - ACPI_VIDEO_FIRST_LEVEL;
 371			return 0;
 372		}
 373
 374	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
 375	return -EINVAL;
 376}
 377
 378/*
 379 * For some buggy _BQC methods, we need to add a constant value to
 380 * the _BQC return value to get the actual current brightness level
 381 */
 382
 383static int bqc_offset_aml_bug_workaround;
 384static int video_set_bqc_offset(const struct dmi_system_id *d)
 385{
 386	bqc_offset_aml_bug_workaround = 9;
 387	return 0;
 388}
 389
 390static int video_set_device_id_scheme(const struct dmi_system_id *d)
 391{
 392	device_id_scheme = true;
 393	return 0;
 394}
 395
 396static int video_enable_only_lcd(const struct dmi_system_id *d)
 397{
 398	only_lcd = true;
 399	return 0;
 400}
 401
 402static int video_set_report_key_events(const struct dmi_system_id *id)
 403{
 404	if (report_key_events == -1)
 405		report_key_events = (uintptr_t)id->driver_data;
 406	return 0;
 407}
 408
 409static int video_hw_changes_brightness(
 410	const struct dmi_system_id *d)
 411{
 412	if (hw_changes_brightness == -1)
 413		hw_changes_brightness = 1;
 414	return 0;
 415}
 416
 417static const struct dmi_system_id video_dmi_table[] = {
 418	/*
 419	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 420	 */
 421	{
 422	 .callback = video_set_bqc_offset,
 423	 .ident = "Acer Aspire 5720",
 424	 .matches = {
 425		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 426		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 427		},
 428	},
 429	{
 430	 .callback = video_set_bqc_offset,
 431	 .ident = "Acer Aspire 5710Z",
 432	 .matches = {
 433		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 434		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 435		},
 436	},
 437	{
 438	 .callback = video_set_bqc_offset,
 439	 .ident = "eMachines E510",
 440	 .matches = {
 441		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 442		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 443		},
 444	},
 445	{
 446	 .callback = video_set_bqc_offset,
 447	 .ident = "Acer Aspire 5315",
 448	 .matches = {
 449		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 450		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 451		},
 452	},
 453	{
 454	 .callback = video_set_bqc_offset,
 455	 .ident = "Acer Aspire 7720",
 456	 .matches = {
 457		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 458		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 459		},
 460	},
 461
 462	/*
 463	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
 464	 * but the IDs actually follow the Device ID Scheme.
 465	 */
 466	{
 467	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 468	 .callback = video_set_device_id_scheme,
 469	 .ident = "ESPRIMO Mobile M9410",
 470	 .matches = {
 471		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 472		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 473		},
 474	},
 475	/*
 476	 * Some machines have multiple video output devices, but only the one
 477	 * that is the type of LCD can do the backlight control so we should not
 478	 * register backlight interface for other video output devices.
 479	 */
 480	{
 481	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 482	 .callback = video_enable_only_lcd,
 483	 .ident = "ESPRIMO Mobile M9410",
 484	 .matches = {
 485		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 486		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 487		},
 488	},
 489	/*
 490	 * Some machines report wrong key events on the acpi-bus, suppress
 491	 * key event reporting on these.  Note this is only intended to work
 492	 * around events which are plain wrong. In some cases we get double
 493	 * events, in this case acpi-video is considered the canonical source
 494	 * and the events from the other source should be filtered. E.g.
 495	 * by calling acpi_video_handles_brightness_key_presses() from the
 496	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
 497	 */
 498	{
 499	 .callback = video_set_report_key_events,
 500	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
 501	 .ident = "Dell Vostro V131",
 502	 .matches = {
 503		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 504		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
 505		},
 506	},
 507	{
 508	 .callback = video_set_report_key_events,
 509	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
 510	 .ident = "Dell Vostro 3350",
 511	 .matches = {
 512		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 513		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
 514		},
 515	},
 516	/*
 517	 * Some machines change the brightness themselves when a brightness
 518	 * hotkey gets pressed, despite us telling them not to. In this case
 519	 * acpi_video_device_notify() should only call backlight_force_update(
 520	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
 521	 */
 522	{
 523	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
 524	 .callback = video_hw_changes_brightness,
 525	 .ident = "Packard Bell EasyNote MZ35",
 526	 .matches = {
 527		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
 528		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
 529		},
 530	},
 531	{}
 532};
 533
 534static unsigned long long
 535acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 536			      unsigned long long bqc_value)
 537{
 538	unsigned long long level;
 539
 540	if (device->brightness->flags._BQC_use_index) {
 541		/*
 542		 * _BQC returns an index that doesn't account for the first 2
 543		 * items with special meaning (see enum acpi_video_level_idx),
 544		 * so we need to compensate for that by offsetting ourselves
 545		 */
 546		if (device->brightness->flags._BCL_reversed)
 547			bqc_value = device->brightness->count -
 548				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
 549
 550		level = device->brightness->levels[bqc_value +
 551						   ACPI_VIDEO_FIRST_LEVEL];
 552	} else {
 553		level = bqc_value;
 554	}
 555
 556	level += bqc_offset_aml_bug_workaround;
 557
 558	return level;
 559}
 560
 561static int
 562acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 563					unsigned long long *level, bool raw)
 564{
 565	acpi_status status = AE_OK;
 566	int i;
 567
 568	if (device->cap._BQC || device->cap._BCQ) {
 569		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 570
 571		status = acpi_evaluate_integer(device->dev->handle, buf,
 572						NULL, level);
 573		if (ACPI_SUCCESS(status)) {
 574			if (raw) {
 575				/*
 576				 * Caller has indicated he wants the raw
 577				 * value returned by _BQC, so don't furtherly
 578				 * mess with the value.
 579				 */
 580				return 0;
 581			}
 582
 583			*level = acpi_video_bqc_value_to_level(device, *level);
 584
 585			for (i = ACPI_VIDEO_FIRST_LEVEL;
 586			     i < device->brightness->count; i++)
 587				if (device->brightness->levels[i] == *level) {
 588					device->brightness->curr = *level;
 589					return 0;
 590				}
 591			/*
 592			 * BQC returned an invalid level.
 593			 * Stop using it.
 594			 */
 595			acpi_handle_info(device->dev->handle,
 596					 "%s returned an invalid level", buf);
 597			device->cap._BQC = device->cap._BCQ = 0;
 598		} else {
 599			/*
 600			 * Fixme:
 601			 * should we return an error or ignore this failure?
 602			 * dev->brightness->curr is a cached value which stores
 603			 * the correct current backlight level in most cases.
 604			 * ACPI video backlight still works w/ buggy _BQC.
 605			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 606			 */
 607			acpi_handle_info(device->dev->handle,
 608					 "%s evaluation failed", buf);
 609			device->cap._BQC = device->cap._BCQ = 0;
 610		}
 611	}
 612
 613	*level = device->brightness->curr;
 614	return 0;
 615}
 616
 617static int
 618acpi_video_device_EDID(struct acpi_video_device *device,
 619		       union acpi_object **edid, ssize_t length)
 620{
 621	int status;
 622	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 623	union acpi_object *obj;
 624	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 625	struct acpi_object_list args = { 1, &arg0 };
 626
 627
 628	*edid = NULL;
 629
 630	if (!device)
 631		return -ENODEV;
 632	if (length == 128)
 633		arg0.integer.value = 1;
 634	else if (length == 256)
 635		arg0.integer.value = 2;
 636	else
 637		return -EINVAL;
 638
 639	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 640	if (ACPI_FAILURE(status))
 641		return -ENODEV;
 642
 643	obj = buffer.pointer;
 644
 645	if (obj && obj->type == ACPI_TYPE_BUFFER)
 646		*edid = obj;
 647	else {
 648		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
 649		status = -EFAULT;
 650		kfree(obj);
 651	}
 652
 653	return status;
 654}
 655
 656/* bus */
 657
 658/*
 659 *  Arg:
 660 *	video		: video bus device pointer
 661 *	bios_flag	:
 662 *		0.	The system BIOS should NOT automatically switch(toggle)
 663 *			the active display output.
 664 *		1.	The system BIOS should automatically switch (toggle) the
 665 *			active display output. No switch event.
 666 *		2.	The _DGS value should be locked.
 667 *		3.	The system BIOS should not automatically switch (toggle) the
 668 *			active display output, but instead generate the display switch
 669 *			event notify code.
 670 *	lcd_flag	:
 671 *		0.	The system BIOS should automatically control the brightness level
 672 *			of the LCD when:
 673 *			- the power changes from AC to DC (ACPI appendix B)
 674 *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
 675 *		1.	The system BIOS should NOT automatically control the brightness
 676 *			level of the LCD when:
 677 *			- the power changes from AC to DC (ACPI appendix B)
 678 *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
 679 *  Return Value:
 680 *		-EINVAL	wrong arg.
 681 */
 682
 683static int
 684acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 685{
 686	acpi_status status;
 687
 688	if (!video->cap._DOS)
 689		return 0;
 690
 691	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 692		return -EINVAL;
 693	video->dos_setting = (lcd_flag << 2) | bios_flag;
 694	status = acpi_execute_simple_method(video->device->handle, "_DOS",
 695					    (lcd_flag << 2) | bios_flag);
 696	if (ACPI_FAILURE(status))
 697		return -EIO;
 698
 699	return 0;
 700}
 701
 702/*
 703 * Simple comparison function used to sort backlight levels.
 704 */
 705
 706static int
 707acpi_video_cmp_level(const void *a, const void *b)
 708{
 709	return *(int *)a - *(int *)b;
 710}
 711
 712/*
 713 * Decides if _BQC/_BCQ for this system is usable
 714 *
 715 * We do this by changing the level first and then read out the current
 716 * brightness level, if the value does not match, find out if it is using
 717 * index. If not, clear the _BQC/_BCQ capability.
 718 */
 719static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 720				int max_level, int current_level)
 721{
 722	struct acpi_video_device_brightness *br = device->brightness;
 723	int result;
 724	unsigned long long level;
 725	int test_level;
 726
 727	/* don't mess with existing known broken systems */
 728	if (bqc_offset_aml_bug_workaround)
 729		return 0;
 730
 731	/*
 732	 * Some systems always report current brightness level as maximum
 733	 * through _BQC, we need to test another value for them. However,
 734	 * there is a subtlety:
 735	 *
 736	 * If the _BCL package ordering is descending, the first level
 737	 * (br->levels[2]) is likely to be 0, and if the number of levels
 738	 * matches the number of steps, we might confuse a returned level to
 739	 * mean the index.
 740	 *
 741	 * For example:
 742	 *
 743	 *     current_level = max_level = 100
 744	 *     test_level = 0
 745	 *     returned level = 100
 746	 *
 747	 * In this case 100 means the level, not the index, and _BCM failed.
 748	 * Still, if the _BCL package ordering is descending, the index of
 749	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
 750	 *
 751	 * This causes all _BQC calls to return bogus values causing weird
 752	 * behavior from the user's perspective.  For example:
 753	 *
 754	 * xbacklight -set 10; xbacklight -set 20;
 755	 *
 756	 * would flash to 90% and then slowly down to the desired level (20).
 757	 *
 758	 * The solution is simple; test anything other than the first level
 759	 * (e.g. 1).
 760	 */
 761	test_level = current_level == max_level
 762		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
 763		: max_level;
 764
 765	result = acpi_video_device_lcd_set_level(device, test_level);
 766	if (result)
 767		return result;
 768
 769	result = acpi_video_device_lcd_get_level_current(device, &level, true);
 770	if (result)
 771		return result;
 772
 773	if (level != test_level) {
 774		/* buggy _BQC found, need to find out if it uses index */
 775		if (level < br->count) {
 776			if (br->flags._BCL_reversed)
 777				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
 778			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
 779				br->flags._BQC_use_index = 1;
 780		}
 781
 782		if (!br->flags._BQC_use_index)
 783			device->cap._BQC = device->cap._BCQ = 0;
 784	}
 785
 786	return 0;
 787}
 788
 789int acpi_video_get_levels(struct acpi_device *device,
 790			  struct acpi_video_device_brightness **dev_br,
 791			  int *pmax_level)
 792{
 793	union acpi_object *obj = NULL;
 794	int i, max_level = 0, count = 0, level_ac_battery = 0;
 795	union acpi_object *o;
 796	struct acpi_video_device_brightness *br = NULL;
 797	int result = 0;
 798	u32 value;
 799
 800	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
 801		acpi_handle_debug(device->handle,
 802				  "Could not query available LCD brightness level\n");
 803		result = -ENODEV;
 804		goto out;
 805	}
 806
 807	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
 808		result = -EINVAL;
 809		goto out;
 810	}
 811
 812	br = kzalloc(sizeof(*br), GFP_KERNEL);
 813	if (!br) {
 814		result = -ENOMEM;
 815		goto out;
 816	}
 817
 818	/*
 819	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
 820	 * in order to account for buggy BIOS which don't export the first two
 821	 * special levels (see below)
 822	 */
 823	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
 824				   sizeof(*br->levels),
 825				   GFP_KERNEL);
 826	if (!br->levels) {
 827		result = -ENOMEM;
 828		goto out_free;
 829	}
 830
 831	for (i = 0; i < obj->package.count; i++) {
 832		o = (union acpi_object *)&obj->package.elements[i];
 833		if (o->type != ACPI_TYPE_INTEGER) {
 834			acpi_handle_info(device->handle, "Invalid data\n");
 835			continue;
 836		}
 837		value = (u32) o->integer.value;
 838		/* Skip duplicate entries */
 839		if (count > ACPI_VIDEO_FIRST_LEVEL
 840		    && br->levels[count - 1] == value)
 841			continue;
 842
 843		br->levels[count] = value;
 844
 845		if (br->levels[count] > max_level)
 846			max_level = br->levels[count];
 847		count++;
 848	}
 849
 850	/*
 851	 * some buggy BIOS don't export the levels
 852	 * when machine is on AC/Battery in _BCL package.
 853	 * In this case, the first two elements in _BCL packages
 854	 * are also supported brightness levels that OS should take care of.
 855	 */
 856	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
 857		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
 858			level_ac_battery++;
 859		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
 860			level_ac_battery++;
 861	}
 862
 863	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
 864		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
 865		br->flags._BCL_no_ac_battery_levels = 1;
 866		for (i = (count - 1 + level_ac_battery);
 867		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
 868			br->levels[i] = br->levels[i - level_ac_battery];
 869		count += level_ac_battery;
 870	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
 871		acpi_handle_info(device->handle,
 872				 "Too many duplicates in _BCL package");
 873
 874	/* Check if the _BCL package is in a reversed order */
 875	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
 876		br->flags._BCL_reversed = 1;
 877		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
 878		     count - ACPI_VIDEO_FIRST_LEVEL,
 879		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
 880		     acpi_video_cmp_level, NULL);
 881	} else if (max_level != br->levels[count - 1])
 882		acpi_handle_info(device->handle,
 883				 "Found unordered _BCL package");
 884
 885	br->count = count;
 886	*dev_br = br;
 887	if (pmax_level)
 888		*pmax_level = max_level;
 889
 890out:
 891	kfree(obj);
 892	return result;
 893out_free:
 894	kfree(br);
 895	goto out;
 896}
 897EXPORT_SYMBOL(acpi_video_get_levels);
 898
 899/*
 900 *  Arg:
 901 *	device	: video output device (LCD, CRT, ..)
 902 *
 903 *  Return Value:
 904 *	Maximum brightness level
 905 *
 906 *  Allocate and initialize device->brightness.
 907 */
 908
 909static int
 910acpi_video_init_brightness(struct acpi_video_device *device)
 911{
 912	int i, max_level = 0;
 913	unsigned long long level, level_old;
 914	struct acpi_video_device_brightness *br = NULL;
 915	int result;
 916
 917	result = acpi_video_get_levels(device->dev, &br, &max_level);
 918	if (result)
 919		return result;
 920	device->brightness = br;
 921
 922	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 923	br->curr = level = max_level;
 924
 925	if (!device->cap._BQC)
 926		goto set_level;
 927
 928	result = acpi_video_device_lcd_get_level_current(device,
 929							 &level_old, true);
 930	if (result)
 931		goto out_free_levels;
 932
 933	result = acpi_video_bqc_quirk(device, max_level, level_old);
 934	if (result)
 935		goto out_free_levels;
 936	/*
 937	 * cap._BQC may get cleared due to _BQC is found to be broken
 938	 * in acpi_video_bqc_quirk, so check again here.
 939	 */
 940	if (!device->cap._BQC)
 941		goto set_level;
 942
 943	level = acpi_video_bqc_value_to_level(device, level_old);
 944	/*
 945	 * On some buggy laptops, _BQC returns an uninitialized
 946	 * value when invoked for the first time, i.e.
 947	 * level_old is invalid (no matter whether it's a level
 948	 * or an index). Set the backlight to max_level in this case.
 949	 */
 950	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
 951		if (level == br->levels[i])
 952			break;
 953	if (i == br->count || !level)
 954		level = max_level;
 955
 956set_level:
 957	result = acpi_video_device_lcd_set_level(device, level);
 958	if (result)
 959		goto out_free_levels;
 960
 961	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
 962			  br->count - ACPI_VIDEO_FIRST_LEVEL);
 963
 964	return 0;
 965
 966out_free_levels:
 967	kfree(br->levels);
 968	kfree(br);
 969	device->brightness = NULL;
 970	return result;
 971}
 972
 973/*
 974 *  Arg:
 975 *	device	: video output device (LCD, CRT, ..)
 976 *
 977 *  Return Value:
 978 *	None
 979 *
 980 *  Find out all required AML methods defined under the output
 981 *  device.
 982 */
 983
 984static void acpi_video_device_find_cap(struct acpi_video_device *device)
 985{
 986	if (acpi_has_method(device->dev->handle, "_ADR"))
 987		device->cap._ADR = 1;
 988	if (acpi_has_method(device->dev->handle, "_BCL"))
 989		device->cap._BCL = 1;
 990	if (acpi_has_method(device->dev->handle, "_BCM"))
 991		device->cap._BCM = 1;
 992	if (acpi_has_method(device->dev->handle, "_BQC")) {
 993		device->cap._BQC = 1;
 994	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 995		acpi_handle_info(device->dev->handle,
 996				 "_BCQ is used instead of _BQC\n");
 997		device->cap._BCQ = 1;
 998	}
 999
1000	if (acpi_has_method(device->dev->handle, "_DDC"))
1001		device->cap._DDC = 1;
1002}
1003
1004/*
1005 *  Arg:
1006 *	device	: video output device (VGA)
1007 *
1008 *  Return Value:
1009 *	None
1010 *
1011 *  Find out all required AML methods defined under the video bus device.
1012 */
1013
1014static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1015{
1016	if (acpi_has_method(video->device->handle, "_DOS"))
1017		video->cap._DOS = 1;
1018	if (acpi_has_method(video->device->handle, "_DOD"))
1019		video->cap._DOD = 1;
1020	if (acpi_has_method(video->device->handle, "_ROM"))
1021		video->cap._ROM = 1;
1022	if (acpi_has_method(video->device->handle, "_GPD"))
1023		video->cap._GPD = 1;
1024	if (acpi_has_method(video->device->handle, "_SPD"))
1025		video->cap._SPD = 1;
1026	if (acpi_has_method(video->device->handle, "_VPO"))
1027		video->cap._VPO = 1;
1028}
1029
1030/*
1031 * Check whether the video bus device has required AML method to
1032 * support the desired features
1033 */
1034
1035static int acpi_video_bus_check(struct acpi_video_bus *video)
1036{
1037	acpi_status status = -ENOENT;
1038	struct pci_dev *dev;
1039
1040	if (!video)
1041		return -EINVAL;
1042
1043	dev = acpi_get_pci_dev(video->device->handle);
1044	if (!dev)
1045		return -ENODEV;
1046	pci_dev_put(dev);
1047
1048	/*
1049	 * Since there is no HID, CID and so on for VGA driver, we have
1050	 * to check well known required nodes.
1051	 */
1052
1053	/* Does this device support video switching? */
1054	if (video->cap._DOS || video->cap._DOD) {
1055		if (!video->cap._DOS) {
1056			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1057				acpi_device_bid(video->device));
1058		}
1059		video->flags.multihead = 1;
1060		status = 0;
1061	}
1062
1063	/* Does this device support retrieving a video ROM? */
1064	if (video->cap._ROM) {
1065		video->flags.rom = 1;
1066		status = 0;
1067	}
1068
1069	/* Does this device support configuring which video device to POST? */
1070	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1071		video->flags.post = 1;
1072		status = 0;
1073	}
1074
1075	return status;
1076}
1077
1078/*
1079 * --------------------------------------------------------------------------
1080 *                               Driver Interface
1081 * --------------------------------------------------------------------------
1082 */
1083
1084/* device interface */
1085static struct acpi_video_device_attrib *
1086acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1087{
1088	struct acpi_video_enumerated_device *ids;
1089	int i;
1090
1091	for (i = 0; i < video->attached_count; i++) {
1092		ids = &video->attached_array[i];
1093		if ((ids->value.int_val & 0xffff) == device_id)
1094			return &ids->value.attrib;
1095	}
1096
1097	return NULL;
1098}
1099
1100static int
1101acpi_video_get_device_type(struct acpi_video_bus *video,
1102			   unsigned long device_id)
1103{
1104	struct acpi_video_enumerated_device *ids;
1105	int i;
1106
1107	for (i = 0; i < video->attached_count; i++) {
1108		ids = &video->attached_array[i];
1109		if ((ids->value.int_val & 0xffff) == device_id)
1110			return ids->value.int_val;
1111	}
1112
1113	return 0;
1114}
1115
1116static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
1117{
1118	struct acpi_video_bus *video = arg;
1119	struct acpi_video_device_attrib *attribute;
1120	struct acpi_video_device *data;
1121	unsigned long long device_id;
1122	acpi_status status;
1123	int device_type;
1124
1125	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1126	/* Skip devices without _ADR instead of failing. */
1127	if (ACPI_FAILURE(status))
1128		goto exit;
1129
1130	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1131	if (!data) {
1132		dev_dbg(&device->dev, "Cannot attach\n");
1133		return -ENOMEM;
1134	}
1135
1136	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1137	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1138	device->driver_data = data;
1139
1140	data->device_id = device_id;
1141	data->video = video;
1142	data->dev = device;
1143	INIT_DELAYED_WORK(&data->switch_brightness_work,
1144			  acpi_video_switch_brightness);
1145
1146	attribute = acpi_video_get_device_attr(video, device_id);
1147
1148	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1149		switch (attribute->display_type) {
1150		case ACPI_VIDEO_DISPLAY_CRT:
1151			data->flags.crt = 1;
1152			break;
1153		case ACPI_VIDEO_DISPLAY_TV:
1154			data->flags.tvout = 1;
1155			break;
1156		case ACPI_VIDEO_DISPLAY_DVI:
1157			data->flags.dvi = 1;
1158			break;
1159		case ACPI_VIDEO_DISPLAY_LCD:
1160			data->flags.lcd = 1;
1161			break;
1162		default:
1163			data->flags.unknown = 1;
1164			break;
1165		}
1166		if (attribute->bios_can_detect)
1167			data->flags.bios = 1;
1168	} else {
1169		/* Check for legacy IDs */
1170		device_type = acpi_video_get_device_type(video, device_id);
1171		/* Ignore bits 16 and 18-20 */
1172		switch (device_type & 0xffe2ffff) {
1173		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1174			data->flags.crt = 1;
1175			break;
1176		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1177			data->flags.lcd = 1;
1178			break;
1179		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1180			data->flags.tvout = 1;
1181			break;
1182		default:
1183			data->flags.unknown = 1;
1184		}
1185	}
1186
1187	acpi_video_device_bind(video, data);
1188	acpi_video_device_find_cap(data);
1189
1190	if (data->cap._BCM && data->cap._BCL)
1191		may_report_brightness_keys = true;
1192
1193	mutex_lock(&video->device_list_lock);
1194	list_add_tail(&data->entry, &video->video_device_list);
1195	mutex_unlock(&video->device_list_lock);
1196
1197exit:
1198	video->child_count++;
1199	return 0;
1200}
1201
1202/*
1203 *  Arg:
1204 *	video	: video bus device
1205 *
1206 *  Return:
1207 *	none
1208 *
1209 *  Enumerate the video device list of the video bus,
1210 *  bind the ids with the corresponding video devices
1211 *  under the video bus.
1212 */
1213
1214static void acpi_video_device_rebind(struct acpi_video_bus *video)
1215{
1216	struct acpi_video_device *dev;
1217
1218	mutex_lock(&video->device_list_lock);
1219
1220	list_for_each_entry(dev, &video->video_device_list, entry)
1221		acpi_video_device_bind(video, dev);
1222
1223	mutex_unlock(&video->device_list_lock);
1224}
1225
1226/*
1227 *  Arg:
1228 *	video	: video bus device
1229 *	device	: video output device under the video
1230 *		bus
1231 *
1232 *  Return:
1233 *	none
1234 *
1235 *  Bind the ids with the corresponding video devices
1236 *  under the video bus.
1237 */
1238
1239static void
1240acpi_video_device_bind(struct acpi_video_bus *video,
1241		       struct acpi_video_device *device)
1242{
1243	struct acpi_video_enumerated_device *ids;
1244	int i;
1245
1246	for (i = 0; i < video->attached_count; i++) {
1247		ids = &video->attached_array[i];
1248		if (device->device_id == (ids->value.int_val & 0xffff)) {
1249			ids->bind_info = device;
1250			acpi_handle_debug(video->device->handle, "%s: %d\n",
1251					  __func__, i);
1252		}
1253	}
1254}
1255
1256static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1257{
1258	struct acpi_video_bus *video = device->video;
1259	int i;
1260
1261	/*
1262	 * If we have a broken _DOD or we have more than 8 output devices
1263	 * under the graphics controller node that we can't proper deal with
1264	 * in the operation region code currently, no need to test.
1265	 */
1266	if (!video->attached_count || video->child_count > 8)
1267		return true;
1268
1269	for (i = 0; i < video->attached_count; i++) {
1270		if ((video->attached_array[i].value.int_val & 0xfff) ==
1271		    (device->device_id & 0xfff))
1272			return true;
1273	}
1274
1275	return false;
1276}
1277
1278/*
1279 *  Arg:
1280 *	video	: video bus device
1281 *
1282 *  Return:
1283 *	< 0	: error
1284 *
1285 *  Call _DOD to enumerate all devices attached to display adapter
1286 *
1287 */
1288
1289static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1290{
1291	int status;
1292	int count;
1293	int i;
1294	struct acpi_video_enumerated_device *active_list;
1295	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1296	union acpi_object *dod = NULL;
1297	union acpi_object *obj;
1298
1299	if (!video->cap._DOD)
1300		return AE_NOT_EXIST;
1301
1302	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1303	if (ACPI_FAILURE(status)) {
1304		acpi_handle_info(video->device->handle,
1305				 "_DOD evaluation failed: %s\n",
1306				 acpi_format_exception(status));
1307		return status;
1308	}
1309
1310	dod = buffer.pointer;
1311	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1312		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1313		status = -EFAULT;
1314		goto out;
1315	}
1316
1317	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1318			  dod->package.count);
1319
1320	active_list = kcalloc(1 + dod->package.count,
1321			      sizeof(struct acpi_video_enumerated_device),
1322			      GFP_KERNEL);
1323	if (!active_list) {
1324		status = -ENOMEM;
1325		goto out;
1326	}
1327
1328	count = 0;
1329	for (i = 0; i < dod->package.count; i++) {
1330		obj = &dod->package.elements[i];
1331
1332		if (obj->type != ACPI_TYPE_INTEGER) {
1333			acpi_handle_info(video->device->handle,
1334					 "Invalid _DOD data in element %d\n", i);
1335			continue;
1336		}
1337
1338		active_list[count].value.int_val = obj->integer.value;
1339		active_list[count].bind_info = NULL;
1340
1341		acpi_handle_debug(video->device->handle,
1342				  "_DOD element[%d] = %d\n", i,
1343				  (int)obj->integer.value);
1344
1345		count++;
1346	}
1347
1348	kfree(video->attached_array);
1349
1350	video->attached_array = active_list;
1351	video->attached_count = count;
1352
1353out:
1354	kfree(buffer.pointer);
1355	return status;
1356}
1357
1358static int
1359acpi_video_get_next_level(struct acpi_video_device *device,
1360			  u32 level_current, u32 event)
1361{
1362	int min, max, min_above, max_below, i, l, delta = 255;
1363	max = max_below = 0;
1364	min = min_above = 255;
1365	/* Find closest level to level_current */
1366	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1367		l = device->brightness->levels[i];
1368		if (abs(l - level_current) < abs(delta)) {
1369			delta = l - level_current;
1370			if (!delta)
1371				break;
1372		}
1373	}
1374	/* Adjust level_current to closest available level */
1375	level_current += delta;
1376	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1377		l = device->brightness->levels[i];
1378		if (l < min)
1379			min = l;
1380		if (l > max)
1381			max = l;
1382		if (l < min_above && l > level_current)
1383			min_above = l;
1384		if (l > max_below && l < level_current)
1385			max_below = l;
1386	}
1387
1388	switch (event) {
1389	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1390		return (level_current < max) ? min_above : min;
1391	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1392		return (level_current < max) ? min_above : max;
1393	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1394		return (level_current > min) ? max_below : min;
1395	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1396	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1397		return 0;
1398	default:
1399		return level_current;
1400	}
1401}
1402
1403static void
1404acpi_video_switch_brightness(struct work_struct *work)
1405{
1406	struct acpi_video_device *device = container_of(to_delayed_work(work),
1407			     struct acpi_video_device, switch_brightness_work);
1408	unsigned long long level_current, level_next;
1409	int event = device->switch_brightness_event;
1410	int result = -EINVAL;
1411
1412	/* no warning message if acpi_backlight=vendor or a quirk is used */
1413	if (!device->backlight)
1414		return;
1415
1416	if (!device->brightness)
1417		goto out;
1418
1419	result = acpi_video_device_lcd_get_level_current(device,
1420							 &level_current,
1421							 false);
1422	if (result)
1423		goto out;
1424
1425	level_next = acpi_video_get_next_level(device, level_current, event);
1426
1427	result = acpi_video_device_lcd_set_level(device, level_next);
1428
1429	if (!result)
1430		backlight_force_update(device->backlight,
1431				       BACKLIGHT_UPDATE_HOTKEY);
1432
1433out:
1434	if (result)
1435		acpi_handle_info(device->dev->handle,
1436				 "Failed to switch brightness\n");
1437}
1438
1439int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1440			void **edid)
1441{
1442	struct acpi_video_bus *video;
1443	struct acpi_video_device *video_device;
1444	union acpi_object *buffer = NULL;
1445	acpi_status status;
1446	int i, length;
1447
1448	if (!device || !acpi_driver_data(device))
1449		return -EINVAL;
1450
1451	video = acpi_driver_data(device);
1452
1453	for (i = 0; i < video->attached_count; i++) {
1454		video_device = video->attached_array[i].bind_info;
1455		length = 256;
1456
1457		if (!video_device)
1458			continue;
1459
1460		if (!video_device->cap._DDC)
1461			continue;
1462
1463		if (type) {
1464			switch (type) {
1465			case ACPI_VIDEO_DISPLAY_CRT:
1466				if (!video_device->flags.crt)
1467					continue;
1468				break;
1469			case ACPI_VIDEO_DISPLAY_TV:
1470				if (!video_device->flags.tvout)
1471					continue;
1472				break;
1473			case ACPI_VIDEO_DISPLAY_DVI:
1474				if (!video_device->flags.dvi)
1475					continue;
1476				break;
1477			case ACPI_VIDEO_DISPLAY_LCD:
1478				if (!video_device->flags.lcd)
1479					continue;
1480				break;
1481			}
1482		} else if (video_device->device_id != device_id) {
1483			continue;
1484		}
1485
1486		status = acpi_video_device_EDID(video_device, &buffer, length);
1487
1488		if (ACPI_FAILURE(status) || !buffer ||
1489		    buffer->type != ACPI_TYPE_BUFFER) {
1490			length = 128;
1491			status = acpi_video_device_EDID(video_device, &buffer,
1492							length);
1493			if (ACPI_FAILURE(status) || !buffer ||
1494			    buffer->type != ACPI_TYPE_BUFFER) {
1495				continue;
1496			}
1497		}
1498
1499		*edid = buffer->buffer.pointer;
1500		return length;
1501	}
1502
1503	return -ENODEV;
1504}
1505EXPORT_SYMBOL(acpi_video_get_edid);
1506
1507static int
1508acpi_video_bus_get_devices(struct acpi_video_bus *video,
1509			   struct acpi_device *device)
1510{
1511	/*
1512	 * There are systems where video module known to work fine regardless
1513	 * of broken _DOD and ignoring returned value here doesn't cause
1514	 * any issues later.
1515	 */
1516	acpi_video_device_enumerate(video);
1517
1518	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
1519}
1520
1521/* acpi_video interface */
1522
1523/*
1524 * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1525 * perform any automatic brightness change on receiving a notification.
1526 */
1527static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1528{
1529	return acpi_video_bus_DOS(video, 0,
1530				  acpi_osi_is_win8() ? 1 : 0);
1531}
1532
1533static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1534{
1535	return acpi_video_bus_DOS(video, 0,
1536				  acpi_osi_is_win8() ? 0 : 1);
1537}
1538
1539static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1540{
1541	struct acpi_video_bus *video = acpi_driver_data(device);
1542	struct input_dev *input;
1543	int keycode = 0;
1544
1545	if (!video || !video->input)
1546		return;
1547
1548	input = video->input;
1549
1550	switch (event) {
1551	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1552					 * most likely via hotkey. */
1553		keycode = KEY_SWITCHVIDEOMODE;
1554		break;
1555
1556	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1557					 * connector. */
1558		acpi_video_device_enumerate(video);
1559		acpi_video_device_rebind(video);
1560		keycode = KEY_SWITCHVIDEOMODE;
1561		break;
1562
1563	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1564		keycode = KEY_SWITCHVIDEOMODE;
1565		break;
1566	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1567		keycode = KEY_VIDEO_NEXT;
1568		break;
1569	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1570		keycode = KEY_VIDEO_PREV;
1571		break;
1572
1573	default:
1574		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1575				  event);
1576		break;
1577	}
1578
1579	if (acpi_notifier_call_chain(device, event, 0))
1580		/* Something vetoed the keypress. */
1581		keycode = 0;
1582
1583	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1584		input_report_key(input, keycode, 1);
1585		input_sync(input);
1586		input_report_key(input, keycode, 0);
1587		input_sync(input);
1588	}
1589}
1590
1591static void brightness_switch_event(struct acpi_video_device *video_device,
1592				    u32 event)
1593{
1594	if (!brightness_switch_enabled)
1595		return;
1596
1597	video_device->switch_brightness_event = event;
1598	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1599}
1600
1601static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1602{
1603	struct acpi_video_device *video_device = data;
1604	struct acpi_device *device = NULL;
1605	struct acpi_video_bus *bus;
1606	struct input_dev *input;
1607	int keycode = 0;
1608
1609	if (!video_device)
1610		return;
1611
1612	device = video_device->dev;
1613	bus = video_device->video;
1614	input = bus->input;
1615
1616	if (hw_changes_brightness > 0) {
1617		if (video_device->backlight)
1618			backlight_force_update(video_device->backlight,
1619					       BACKLIGHT_UPDATE_HOTKEY);
1620		acpi_notifier_call_chain(device, event, 0);
1621		return;
1622	}
1623
1624	switch (event) {
1625	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1626		brightness_switch_event(video_device, event);
1627		keycode = KEY_BRIGHTNESS_CYCLE;
1628		break;
1629	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1630		brightness_switch_event(video_device, event);
1631		keycode = KEY_BRIGHTNESSUP;
1632		break;
1633	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1634		brightness_switch_event(video_device, event);
1635		keycode = KEY_BRIGHTNESSDOWN;
1636		break;
1637	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1638		brightness_switch_event(video_device, event);
1639		keycode = KEY_BRIGHTNESS_ZERO;
1640		break;
1641	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1642		brightness_switch_event(video_device, event);
1643		keycode = KEY_DISPLAY_OFF;
1644		break;
1645	default:
1646		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1647		break;
1648	}
1649
1650	if (keycode)
1651		may_report_brightness_keys = true;
1652
1653	acpi_notifier_call_chain(device, event, 0);
1654
1655	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1656		input_report_key(input, keycode, 1);
1657		input_sync(input);
1658		input_report_key(input, keycode, 0);
1659		input_sync(input);
1660	}
1661}
1662
1663static int acpi_video_resume(struct notifier_block *nb,
1664				unsigned long val, void *ign)
1665{
1666	struct acpi_video_bus *video;
1667	struct acpi_video_device *video_device;
1668	int i;
1669
1670	switch (val) {
1671	case PM_POST_HIBERNATION:
1672	case PM_POST_SUSPEND:
1673	case PM_POST_RESTORE:
1674		video = container_of(nb, struct acpi_video_bus, pm_nb);
1675
1676		dev_info(&video->device->dev, "Restoring backlight state\n");
1677
1678		for (i = 0; i < video->attached_count; i++) {
1679			video_device = video->attached_array[i].bind_info;
1680			if (video_device && video_device->brightness)
1681				acpi_video_device_lcd_set_level(video_device,
1682						video_device->brightness->curr);
1683		}
1684
1685		return NOTIFY_OK;
1686	}
1687	return NOTIFY_DONE;
1688}
1689
1690static acpi_status
1691acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1692			void **return_value)
1693{
1694	struct acpi_device *device = context;
1695	struct acpi_device *sibling;
1696
1697	if (handle == device->handle)
1698		return AE_CTRL_TERMINATE;
1699
1700	sibling = acpi_fetch_acpi_dev(handle);
1701	if (!sibling)
1702		return AE_OK;
1703
1704	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1705			return AE_ALREADY_EXISTS;
1706
1707	return AE_OK;
1708}
1709
1710static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1711{
1712	struct backlight_properties props;
1713	struct pci_dev *pdev;
1714	acpi_handle acpi_parent;
1715	struct device *parent = NULL;
1716	int result;
1717	static int count;
1718	char *name;
1719
1720	result = acpi_video_init_brightness(device);
1721	if (result)
1722		return;
1723
1724	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1725	if (!name)
1726		return;
1727	count++;
1728
1729	acpi_get_parent(device->dev->handle, &acpi_parent);
1730
1731	pdev = acpi_get_pci_dev(acpi_parent);
1732	if (pdev) {
1733		parent = &pdev->dev;
1734		pci_dev_put(pdev);
1735	}
1736
1737	memset(&props, 0, sizeof(struct backlight_properties));
1738	props.type = BACKLIGHT_FIRMWARE;
1739	props.max_brightness =
1740		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1741	device->backlight = backlight_device_register(name,
1742						      parent,
1743						      device,
1744						      &acpi_backlight_ops,
1745						      &props);
1746	kfree(name);
1747	if (IS_ERR(device->backlight)) {
1748		device->backlight = NULL;
1749		return;
1750	}
1751
1752	/*
1753	 * Save current brightness level in case we have to restore it
1754	 * before acpi_video_device_lcd_set_level() is called next time.
1755	 */
1756	device->backlight->props.brightness =
1757			acpi_video_get_brightness(device->backlight);
1758
1759	device->cooling_dev = thermal_cooling_device_register("LCD",
1760				device->dev, &video_cooling_ops);
1761	if (IS_ERR(device->cooling_dev)) {
1762		/*
1763		 * Set cooling_dev to NULL so we don't crash trying to free it.
1764		 * Also, why the hell we are returning early and not attempt to
1765		 * register video output if cooling device registration failed?
1766		 * -- dtor
1767		 */
1768		device->cooling_dev = NULL;
1769		return;
1770	}
1771
1772	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1773		 device->cooling_dev->id);
1774	result = sysfs_create_link(&device->dev->dev.kobj,
1775			&device->cooling_dev->device.kobj,
1776			"thermal_cooling");
1777	if (result)
1778		pr_info("sysfs link creation failed\n");
1779
1780	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1781			&device->dev->dev.kobj, "device");
1782	if (result)
1783		pr_info("Reverse sysfs link creation failed\n");
1784}
1785
1786static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1787{
1788	struct acpi_video_device *dev;
1789	union acpi_object *levels;
1790
1791	mutex_lock(&video->device_list_lock);
1792	list_for_each_entry(dev, &video->video_device_list, entry) {
1793		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1794			kfree(levels);
1795	}
1796	mutex_unlock(&video->device_list_lock);
1797}
1798
1799static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1800{
1801	/*
1802	 * Do not create backlight device for video output
1803	 * device that is not in the enumerated list.
1804	 */
1805	if (!acpi_video_device_in_dod(dev)) {
1806		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1807		return false;
1808	}
1809
1810	if (only_lcd)
1811		return dev->flags.lcd;
1812	return true;
1813}
1814
1815static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1816{
1817	struct acpi_video_device *dev;
1818
1819	if (video->backlight_registered)
1820		return 0;
1821
1822	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1823		return 0;
1824
1825	mutex_lock(&video->device_list_lock);
1826	list_for_each_entry(dev, &video->video_device_list, entry) {
1827		if (acpi_video_should_register_backlight(dev))
1828			acpi_video_dev_register_backlight(dev);
1829	}
1830	mutex_unlock(&video->device_list_lock);
1831
1832	video->backlight_registered = true;
1833
1834	video->pm_nb.notifier_call = acpi_video_resume;
1835	video->pm_nb.priority = 0;
1836	return register_pm_notifier(&video->pm_nb);
1837}
1838
1839static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1840{
1841	if (device->backlight) {
1842		backlight_device_unregister(device->backlight);
1843		device->backlight = NULL;
1844	}
1845	if (device->brightness) {
1846		kfree(device->brightness->levels);
1847		kfree(device->brightness);
1848		device->brightness = NULL;
1849	}
1850	if (device->cooling_dev) {
1851		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1852		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1853		thermal_cooling_device_unregister(device->cooling_dev);
1854		device->cooling_dev = NULL;
1855	}
1856}
1857
1858static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1859{
1860	struct acpi_video_device *dev;
1861	int error;
1862
1863	if (!video->backlight_registered)
1864		return 0;
1865
1866	error = unregister_pm_notifier(&video->pm_nb);
1867
1868	mutex_lock(&video->device_list_lock);
1869	list_for_each_entry(dev, &video->video_device_list, entry)
1870		acpi_video_dev_unregister_backlight(dev);
1871	mutex_unlock(&video->device_list_lock);
1872
1873	video->backlight_registered = false;
1874
1875	return error;
1876}
1877
1878static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1879{
1880	acpi_status status;
1881	struct acpi_device *adev = device->dev;
1882
1883	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1884					     acpi_video_device_notify, device);
1885	if (ACPI_FAILURE(status))
1886		dev_err(&adev->dev, "Error installing notify handler\n");
1887	else
1888		device->flags.notify = 1;
1889}
1890
1891static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1892{
1893	struct input_dev *input;
1894	struct acpi_video_device *dev;
1895	int error;
1896
1897	video->input = input = input_allocate_device();
1898	if (!input) {
1899		error = -ENOMEM;
1900		goto out;
1901	}
1902
1903	error = acpi_video_bus_start_devices(video);
1904	if (error)
1905		goto err_free_input;
1906
1907	snprintf(video->phys, sizeof(video->phys),
1908			"%s/video/input0", acpi_device_hid(video->device));
1909
1910	input->name = acpi_device_name(video->device);
1911	input->phys = video->phys;
1912	input->id.bustype = BUS_HOST;
1913	input->id.product = 0x06;
1914	input->dev.parent = &video->device->dev;
1915	input->evbit[0] = BIT(EV_KEY);
1916	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1917	set_bit(KEY_VIDEO_NEXT, input->keybit);
1918	set_bit(KEY_VIDEO_PREV, input->keybit);
1919	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1920	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1921	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1922	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1923	set_bit(KEY_DISPLAY_OFF, input->keybit);
1924
1925	error = input_register_device(input);
1926	if (error)
1927		goto err_stop_dev;
1928
1929	mutex_lock(&video->device_list_lock);
1930	list_for_each_entry(dev, &video->video_device_list, entry)
1931		acpi_video_dev_add_notify_handler(dev);
1932	mutex_unlock(&video->device_list_lock);
1933
1934	return 0;
1935
1936err_stop_dev:
1937	acpi_video_bus_stop_devices(video);
1938err_free_input:
1939	input_free_device(input);
1940	video->input = NULL;
1941out:
1942	return error;
1943}
1944
1945static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1946{
1947	if (dev->flags.notify) {
1948		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1949					   acpi_video_device_notify);
1950		dev->flags.notify = 0;
1951	}
1952}
1953
1954static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1955{
1956	struct acpi_video_device *dev;
1957
1958	mutex_lock(&video->device_list_lock);
1959	list_for_each_entry(dev, &video->video_device_list, entry)
1960		acpi_video_dev_remove_notify_handler(dev);
1961	mutex_unlock(&video->device_list_lock);
1962
1963	acpi_video_bus_stop_devices(video);
1964	input_unregister_device(video->input);
1965	video->input = NULL;
1966}
1967
1968static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1969{
1970	struct acpi_video_device *dev, *next;
1971
1972	mutex_lock(&video->device_list_lock);
1973	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1974		list_del(&dev->entry);
1975		kfree(dev);
1976	}
1977	mutex_unlock(&video->device_list_lock);
1978
1979	return 0;
1980}
1981
1982static int instance;
1983
1984static int acpi_video_bus_add(struct acpi_device *device)
1985{
1986	struct acpi_video_bus *video;
1987	int error;
1988	acpi_status status;
1989
1990	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1991				acpi_dev_parent(device)->handle, 1,
1992				acpi_video_bus_match, NULL,
1993				device, NULL);
1994	if (status == AE_ALREADY_EXISTS) {
1995		pr_info(FW_BUG
1996			"Duplicate ACPI video bus devices for the"
1997			" same VGA controller, please try module "
1998			"parameter \"video.allow_duplicates=1\""
1999			"if the current driver doesn't work.\n");
2000		if (!allow_duplicates)
2001			return -ENODEV;
2002	}
2003
2004	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2005	if (!video)
2006		return -ENOMEM;
2007
2008	/* a hack to fix the duplicate name "VID" problem on T61 */
2009	if (!strcmp(device->pnp.bus_id, "VID")) {
2010		if (instance)
2011			device->pnp.bus_id[3] = '0' + instance;
2012		instance++;
2013	}
2014	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2015	if (!strcmp(device->pnp.bus_id, "VGA")) {
2016		if (instance)
2017			device->pnp.bus_id[3] = '0' + instance;
2018		instance++;
2019	}
2020
2021	video->device = device;
2022	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2023	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2024	device->driver_data = video;
2025
2026	acpi_video_bus_find_cap(video);
2027	error = acpi_video_bus_check(video);
2028	if (error)
2029		goto err_free_video;
2030
2031	mutex_init(&video->device_list_lock);
2032	INIT_LIST_HEAD(&video->video_device_list);
2033
2034	error = acpi_video_bus_get_devices(video, device);
2035	if (error)
2036		goto err_put_video;
2037
2038	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2039	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2040	       video->flags.multihead ? "yes" : "no",
2041	       video->flags.rom ? "yes" : "no",
2042	       video->flags.post ? "yes" : "no");
2043	mutex_lock(&video_list_lock);
2044	list_add_tail(&video->entry, &video_bus_head);
2045	mutex_unlock(&video_list_lock);
2046
2047	/*
2048	 * The userspace visible backlight_device gets registered separately
2049	 * from acpi_video_register_backlight().
2050	 */
2051	acpi_video_run_bcl_for_osi(video);
2052	acpi_video_bus_add_notify_handler(video);
2053
2054	return 0;
2055
2056err_put_video:
2057	acpi_video_bus_put_devices(video);
2058	kfree(video->attached_array);
2059err_free_video:
2060	kfree(video);
2061	device->driver_data = NULL;
2062
2063	return error;
2064}
2065
2066static void acpi_video_bus_remove(struct acpi_device *device)
2067{
2068	struct acpi_video_bus *video = NULL;
2069
2070
2071	if (!device || !acpi_driver_data(device))
2072		return;
2073
2074	video = acpi_driver_data(device);
2075
2076	mutex_lock(&video_list_lock);
2077	list_del(&video->entry);
2078	mutex_unlock(&video_list_lock);
2079
2080	acpi_video_bus_remove_notify_handler(video);
2081	acpi_video_bus_unregister_backlight(video);
2082	acpi_video_bus_put_devices(video);
2083
2084	kfree(video->attached_array);
2085	kfree(video);
2086}
2087
2088static void acpi_video_bus_register_backlight_work(struct work_struct *ignored)
2089{
2090	acpi_video_register_backlight();
2091}
2092
2093static int __init is_i740(struct pci_dev *dev)
2094{
2095	if (dev->device == 0x00D1)
2096		return 1;
2097	if (dev->device == 0x7000)
2098		return 1;
2099	return 0;
2100}
2101
2102static int __init intel_opregion_present(void)
2103{
2104	int opregion = 0;
2105	struct pci_dev *dev = NULL;
2106	u32 address;
2107
2108	for_each_pci_dev(dev) {
2109		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2110			continue;
2111		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2112			continue;
2113		/* We don't want to poke around undefined i740 registers */
2114		if (is_i740(dev))
2115			continue;
2116		pci_read_config_dword(dev, 0xfc, &address);
2117		if (!address)
2118			continue;
2119		opregion = 1;
2120	}
2121	return opregion;
2122}
2123
2124/* Check if the chassis-type indicates there is no builtin LCD panel */
2125static bool dmi_is_desktop(void)
2126{
2127	const char *chassis_type;
2128	unsigned long type;
2129
2130	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2131	if (!chassis_type)
2132		return false;
2133
2134	if (kstrtoul(chassis_type, 10, &type) != 0)
2135		return false;
2136
2137	switch (type) {
2138	case 0x03: /* Desktop */
2139	case 0x04: /* Low Profile Desktop */
2140	case 0x05: /* Pizza Box */
2141	case 0x06: /* Mini Tower */
2142	case 0x07: /* Tower */
2143	case 0x10: /* Lunch Box */
2144	case 0x11: /* Main Server Chassis */
2145		return true;
2146	}
2147
2148	return false;
2149}
2150
2151/*
2152 * We're seeing a lot of bogus backlight interfaces on newer machines
2153 * without a LCD such as desktops, servers and HDMI sticks. Checking the
2154 * lcd flag fixes this, enable this by default on any machines which are:
2155 * 1.  Win8 ready (where we also prefer the native backlight driver, so
2156 *     normally the acpi_video code should not register there anyways); *and*
2157 * 2.1 Report a desktop/server DMI chassis-type, or
2158 * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2159       backlight control)
2160 */
2161static bool should_check_lcd_flag(void)
2162{
2163	if (!acpi_osi_is_win8())
2164		return false;
2165
2166	if (dmi_is_desktop())
2167		return true;
2168
2169	if (acpi_reduced_hardware())
2170		return true;
2171
2172	return false;
2173}
2174
2175/*
2176 * At least one graphics driver has reported that no LCD is connected
2177 * via the native interface. cancel the registration for fallback acpi_video0.
2178 * If another driver still deems this necessary, it can explicitly register it.
2179 */
2180void acpi_video_report_nolcd(void)
2181{
2182	cancel_delayed_work(&video_bus_register_backlight_work);
2183}
2184EXPORT_SYMBOL(acpi_video_report_nolcd);
2185
2186int acpi_video_register(void)
2187{
2188	int ret = 0;
2189
2190	mutex_lock(&register_count_mutex);
2191	if (register_count) {
2192		/*
2193		 * if the function of acpi_video_register is already called,
2194		 * don't register the acpi_video_bus again and return no error.
2195		 */
2196		goto leave;
2197	}
2198
2199	if (only_lcd == -1)
2200		only_lcd = should_check_lcd_flag();
2201
2202	dmi_check_system(video_dmi_table);
2203
2204	ret = acpi_bus_register_driver(&acpi_video_bus);
2205	if (ret)
2206		goto leave;
2207
2208	/*
2209	 * When the acpi_video_bus is loaded successfully, increase
2210	 * the counter reference.
2211	 */
2212	register_count = 1;
2213
2214	/*
2215	 * acpi_video_bus_add() skips registering the userspace visible
2216	 * backlight_device. The intend is for this to be registered by the
2217	 * drm/kms driver calling acpi_video_register_backlight() *after* it is
2218	 * done setting up its own native backlight device. The delayed work
2219	 * ensures that acpi_video_register_backlight() always gets called
2220	 * eventually, in case there is no drm/kms driver or it is disabled.
2221	 */
2222	if (register_backlight_delay)
2223		schedule_delayed_work(&video_bus_register_backlight_work,
2224				      register_backlight_delay * HZ);
2225
2226leave:
2227	mutex_unlock(&register_count_mutex);
2228	return ret;
2229}
2230EXPORT_SYMBOL(acpi_video_register);
2231
2232void acpi_video_unregister(void)
2233{
2234	mutex_lock(&register_count_mutex);
2235	if (register_count) {
2236		cancel_delayed_work_sync(&video_bus_register_backlight_work);
2237		acpi_bus_unregister_driver(&acpi_video_bus);
2238		register_count = 0;
2239		may_report_brightness_keys = false;
2240	}
2241	mutex_unlock(&register_count_mutex);
2242}
2243EXPORT_SYMBOL(acpi_video_unregister);
2244
2245void acpi_video_register_backlight(void)
2246{
2247	struct acpi_video_bus *video;
2248
2249	mutex_lock(&video_list_lock);
2250	list_for_each_entry(video, &video_bus_head, entry)
2251		acpi_video_bus_register_backlight(video);
2252	mutex_unlock(&video_list_lock);
2253}
2254EXPORT_SYMBOL(acpi_video_register_backlight);
2255
2256bool acpi_video_handles_brightness_key_presses(void)
2257{
2258	return may_report_brightness_keys &&
2259	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2260}
2261EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2262
2263/*
2264 * This is kind of nasty. Hardware using Intel chipsets may require
2265 * the video opregion code to be run first in order to initialise
2266 * state before any ACPI video calls are made. To handle this we defer
2267 * registration of the video class until the opregion code has run.
2268 */
2269
2270static int __init acpi_video_init(void)
2271{
2272	/*
2273	 * Let the module load even if ACPI is disabled (e.g. due to
2274	 * a broken BIOS) so that i915.ko can still be loaded on such
2275	 * old systems without an AcpiOpRegion.
2276	 *
2277	 * acpi_video_register() will report -ENODEV later as well due
2278	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2279	 */
2280	if (acpi_disabled)
2281		return 0;
2282
2283	if (intel_opregion_present())
2284		return 0;
2285
2286	return acpi_video_register();
2287}
2288
2289static void __exit acpi_video_exit(void)
2290{
2291	acpi_video_unregister();
2292}
2293
2294module_init(acpi_video_init);
2295module_exit(acpi_video_exit);