xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision 85d616dd)
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 
36 MODULE_AUTHOR("Bruno Ducrot");
37 MODULE_DESCRIPTION("ACPI Video Driver");
38 MODULE_LICENSE("GPL");
39 
40 static bool brightness_switch_enabled = true;
41 module_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  */
47 static bool allow_duplicates;
48 module_param(allow_duplicates, bool, 0644);
49 
50 static int disable_backlight_sysfs_if = -1;
51 module_param(disable_backlight_sysfs_if, int, 0444);
52 
53 #define REPORT_OUTPUT_KEY_EVENTS		0x01
54 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
55 static int report_key_events = -1;
56 module_param(report_key_events, int, 0644);
57 MODULE_PARM_DESC(report_key_events,
58 	"0: none, 1: output changes, 2: brightness changes, 3: all");
59 
60 static int hw_changes_brightness = -1;
61 module_param(hw_changes_brightness, int, 0644);
62 MODULE_PARM_DESC(hw_changes_brightness,
63 	"Set this to 1 on buggy hw which changes the brightness itself when "
64 	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
65 
66 /*
67  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
68  * assumed even if not actually set.
69  */
70 static bool device_id_scheme = false;
71 module_param(device_id_scheme, bool, 0444);
72 
73 static int only_lcd = -1;
74 module_param(only_lcd, int, 0444);
75 
76 static int register_count;
77 static DEFINE_MUTEX(register_count_mutex);
78 static DEFINE_MUTEX(video_list_lock);
79 static LIST_HEAD(video_bus_head);
80 static int acpi_video_bus_add(struct acpi_device *device);
81 static int acpi_video_bus_remove(struct acpi_device *device);
82 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
83 void acpi_video_detect_exit(void);
84 
85 /*
86  * Indices in the _BCL method response: the first two items are special,
87  * the rest are all supported levels.
88  *
89  * See page 575 of the ACPI spec 3.0
90  */
91 enum acpi_video_level_idx {
92 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
93 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
94 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
95 };
96 
97 static const struct acpi_device_id video_device_ids[] = {
98 	{ACPI_VIDEO_HID, 0},
99 	{"", 0},
100 };
101 MODULE_DEVICE_TABLE(acpi, video_device_ids);
102 
103 static struct acpi_driver acpi_video_bus = {
104 	.name = "video",
105 	.class = ACPI_VIDEO_CLASS,
106 	.ids = video_device_ids,
107 	.ops = {
108 		.add = acpi_video_bus_add,
109 		.remove = acpi_video_bus_remove,
110 		.notify = acpi_video_bus_notify,
111 		},
112 };
113 
114 struct acpi_video_bus_flags {
115 	u8 multihead:1;		/* can switch video heads */
116 	u8 rom:1;		/* can retrieve a video rom */
117 	u8 post:1;		/* can configure the head to */
118 	u8 reserved:5;
119 };
120 
121 struct acpi_video_bus_cap {
122 	u8 _DOS:1;		/* Enable/Disable output switching */
123 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
124 	u8 _ROM:1;		/* Get ROM Data */
125 	u8 _GPD:1;		/* Get POST Device */
126 	u8 _SPD:1;		/* Set POST Device */
127 	u8 _VPO:1;		/* Video POST Options */
128 	u8 reserved:2;
129 };
130 
131 struct acpi_video_device_attrib {
132 	u32 display_index:4;	/* A zero-based instance of the Display */
133 	u32 display_port_attachment:4;	/* This field differentiates the display type */
134 	u32 display_type:4;	/* Describe the specific type in use */
135 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
136 	u32 bios_can_detect:1;	/* BIOS can detect the device */
137 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
138 				   the VGA device. */
139 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
140 	u32 reserved:10;	/* Must be 0 */
141 
142 	/*
143 	 * The device ID might not actually follow the scheme described by this
144 	 * struct acpi_video_device_attrib. If it does, then this bit
145 	 * device_id_scheme is set; otherwise, other fields should be ignored.
146 	 *
147 	 * (but also see the global flag device_id_scheme)
148 	 */
149 	u32 device_id_scheme:1;
150 };
151 
152 struct acpi_video_enumerated_device {
153 	union {
154 		u32 int_val;
155 		struct acpi_video_device_attrib attrib;
156 	} value;
157 	struct acpi_video_device *bind_info;
158 };
159 
160 struct acpi_video_bus {
161 	struct acpi_device *device;
162 	bool backlight_registered;
163 	u8 dos_setting;
164 	struct acpi_video_enumerated_device *attached_array;
165 	u8 attached_count;
166 	u8 child_count;
167 	struct acpi_video_bus_cap cap;
168 	struct acpi_video_bus_flags flags;
169 	struct list_head video_device_list;
170 	struct mutex device_list_lock;	/* protects video_device_list */
171 	struct list_head entry;
172 	struct input_dev *input;
173 	char phys[32];	/* for input device */
174 	struct notifier_block pm_nb;
175 };
176 
177 struct acpi_video_device_flags {
178 	u8 crt:1;
179 	u8 lcd:1;
180 	u8 tvout:1;
181 	u8 dvi:1;
182 	u8 bios:1;
183 	u8 unknown:1;
184 	u8 notify:1;
185 	u8 reserved:1;
186 };
187 
188 struct acpi_video_device_cap {
189 	u8 _ADR:1;		/* Return the unique ID */
190 	u8 _BCL:1;		/* Query list of brightness control levels supported */
191 	u8 _BCM:1;		/* Set the brightness level */
192 	u8 _BQC:1;		/* Get current brightness level */
193 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
194 	u8 _DDC:1;		/* Return the EDID for this device */
195 };
196 
197 struct acpi_video_device {
198 	unsigned long device_id;
199 	struct acpi_video_device_flags flags;
200 	struct acpi_video_device_cap cap;
201 	struct list_head entry;
202 	struct delayed_work switch_brightness_work;
203 	int switch_brightness_event;
204 	struct acpi_video_bus *video;
205 	struct acpi_device *dev;
206 	struct acpi_video_device_brightness *brightness;
207 	struct backlight_device *backlight;
208 	struct thermal_cooling_device *cooling_dev;
209 };
210 
211 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
212 static void acpi_video_device_rebind(struct acpi_video_bus *video);
213 static void acpi_video_device_bind(struct acpi_video_bus *video,
214 				   struct acpi_video_device *device);
215 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
216 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
217 			int level);
218 static int acpi_video_device_lcd_get_level_current(
219 			struct acpi_video_device *device,
220 			unsigned long long *level, bool raw);
221 static int acpi_video_get_next_level(struct acpi_video_device *device,
222 				     u32 level_current, u32 event);
223 static void acpi_video_switch_brightness(struct work_struct *work);
224 
225 /* backlight device sysfs support */
226 static int acpi_video_get_brightness(struct backlight_device *bd)
227 {
228 	unsigned long long cur_level;
229 	int i;
230 	struct acpi_video_device *vd = bl_get_data(bd);
231 
232 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
233 		return -EINVAL;
234 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
235 		if (vd->brightness->levels[i] == cur_level)
236 			return i - ACPI_VIDEO_FIRST_LEVEL;
237 	}
238 	return 0;
239 }
240 
241 static int acpi_video_set_brightness(struct backlight_device *bd)
242 {
243 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
244 	struct acpi_video_device *vd = bl_get_data(bd);
245 
246 	cancel_delayed_work(&vd->switch_brightness_work);
247 	return acpi_video_device_lcd_set_level(vd,
248 				vd->brightness->levels[request_level]);
249 }
250 
251 static const struct backlight_ops acpi_backlight_ops = {
252 	.get_brightness = acpi_video_get_brightness,
253 	.update_status  = acpi_video_set_brightness,
254 };
255 
256 /* thermal cooling device callbacks */
257 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
258 			       unsigned long *state)
259 {
260 	struct acpi_device *device = cooling_dev->devdata;
261 	struct acpi_video_device *video = acpi_driver_data(device);
262 
263 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
264 	return 0;
265 }
266 
267 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
268 			       unsigned long *state)
269 {
270 	struct acpi_device *device = cooling_dev->devdata;
271 	struct acpi_video_device *video = acpi_driver_data(device);
272 	unsigned long long level;
273 	int offset;
274 
275 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
276 		return -EINVAL;
277 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
278 	     offset++)
279 		if (level == video->brightness->levels[offset]) {
280 			*state = video->brightness->count - offset - 1;
281 			return 0;
282 		}
283 
284 	return -EINVAL;
285 }
286 
287 static int
288 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
289 {
290 	struct acpi_device *device = cooling_dev->devdata;
291 	struct acpi_video_device *video = acpi_driver_data(device);
292 	int level;
293 
294 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
295 		return -EINVAL;
296 
297 	state = video->brightness->count - state;
298 	level = video->brightness->levels[state - 1];
299 	return acpi_video_device_lcd_set_level(video, level);
300 }
301 
302 static const struct thermal_cooling_device_ops video_cooling_ops = {
303 	.get_max_state = video_get_max_state,
304 	.get_cur_state = video_get_cur_state,
305 	.set_cur_state = video_set_cur_state,
306 };
307 
308 /*
309  * --------------------------------------------------------------------------
310  *                             Video Management
311  * --------------------------------------------------------------------------
312  */
313 
314 static int
315 acpi_video_device_lcd_query_levels(acpi_handle handle,
316 				   union acpi_object **levels)
317 {
318 	int status;
319 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
320 	union acpi_object *obj;
321 
322 
323 	*levels = NULL;
324 
325 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
326 	if (ACPI_FAILURE(status))
327 		return status;
328 	obj = (union acpi_object *)buffer.pointer;
329 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
330 		acpi_handle_info(handle, "Invalid _BCL data\n");
331 		status = -EFAULT;
332 		goto err;
333 	}
334 
335 	*levels = obj;
336 
337 	return 0;
338 
339 err:
340 	kfree(buffer.pointer);
341 
342 	return status;
343 }
344 
345 static int
346 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
347 {
348 	int status;
349 	int state;
350 
351 	status = acpi_execute_simple_method(device->dev->handle,
352 					    "_BCM", level);
353 	if (ACPI_FAILURE(status)) {
354 		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
355 		return -EIO;
356 	}
357 
358 	device->brightness->curr = level;
359 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
360 	     state++)
361 		if (level == device->brightness->levels[state]) {
362 			if (device->backlight)
363 				device->backlight->props.brightness =
364 					state - ACPI_VIDEO_FIRST_LEVEL;
365 			return 0;
366 		}
367 
368 	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
369 	return -EINVAL;
370 }
371 
372 /*
373  * For some buggy _BQC methods, we need to add a constant value to
374  * the _BQC return value to get the actual current brightness level
375  */
376 
377 static int bqc_offset_aml_bug_workaround;
378 static int video_set_bqc_offset(const struct dmi_system_id *d)
379 {
380 	bqc_offset_aml_bug_workaround = 9;
381 	return 0;
382 }
383 
384 static int video_disable_backlight_sysfs_if(
385 	const struct dmi_system_id *d)
386 {
387 	if (disable_backlight_sysfs_if == -1)
388 		disable_backlight_sysfs_if = 1;
389 	return 0;
390 }
391 
392 static int video_set_device_id_scheme(const struct dmi_system_id *d)
393 {
394 	device_id_scheme = true;
395 	return 0;
396 }
397 
398 static int video_enable_only_lcd(const struct dmi_system_id *d)
399 {
400 	only_lcd = true;
401 	return 0;
402 }
403 
404 static int video_set_report_key_events(const struct dmi_system_id *id)
405 {
406 	if (report_key_events == -1)
407 		report_key_events = (uintptr_t)id->driver_data;
408 	return 0;
409 }
410 
411 static int video_hw_changes_brightness(
412 	const struct dmi_system_id *d)
413 {
414 	if (hw_changes_brightness == -1)
415 		hw_changes_brightness = 1;
416 	return 0;
417 }
418 
419 static const struct dmi_system_id video_dmi_table[] = {
420 	/*
421 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
422 	 */
423 	{
424 	 .callback = video_set_bqc_offset,
425 	 .ident = "Acer Aspire 5720",
426 	 .matches = {
427 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
428 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
429 		},
430 	},
431 	{
432 	 .callback = video_set_bqc_offset,
433 	 .ident = "Acer Aspire 5710Z",
434 	 .matches = {
435 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
436 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
437 		},
438 	},
439 	{
440 	 .callback = video_set_bqc_offset,
441 	 .ident = "eMachines E510",
442 	 .matches = {
443 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
444 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
445 		},
446 	},
447 	{
448 	 .callback = video_set_bqc_offset,
449 	 .ident = "Acer Aspire 5315",
450 	 .matches = {
451 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
452 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
453 		},
454 	},
455 	{
456 	 .callback = video_set_bqc_offset,
457 	 .ident = "Acer Aspire 7720",
458 	 .matches = {
459 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
460 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
461 		},
462 	},
463 
464 	/*
465 	 * Some machines have a broken acpi-video interface for brightness
466 	 * control, but still need an acpi_video_device_lcd_set_level() call
467 	 * on resume to turn the backlight power on.  We Enable backlight
468 	 * control on these systems, but do not register a backlight sysfs
469 	 * as brightness control does not work.
470 	 */
471 	{
472 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
473 	 .callback = video_disable_backlight_sysfs_if,
474 	 .ident = "Toshiba Portege R700",
475 	 .matches = {
476 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
477 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
478 		},
479 	},
480 	{
481 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
482 	 .callback = video_disable_backlight_sysfs_if,
483 	 .ident = "Toshiba Portege R830",
484 	 .matches = {
485 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
486 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
487 		},
488 	},
489 	{
490 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
491 	 .callback = video_disable_backlight_sysfs_if,
492 	 .ident = "Toshiba Satellite R830",
493 	 .matches = {
494 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
495 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
496 		},
497 	},
498 	/*
499 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
500 	 * but the IDs actually follow the Device ID Scheme.
501 	 */
502 	{
503 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
504 	 .callback = video_set_device_id_scheme,
505 	 .ident = "ESPRIMO Mobile M9410",
506 	 .matches = {
507 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
508 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
509 		},
510 	},
511 	/*
512 	 * Some machines have multiple video output devices, but only the one
513 	 * that is the type of LCD can do the backlight control so we should not
514 	 * register backlight interface for other video output devices.
515 	 */
516 	{
517 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
518 	 .callback = video_enable_only_lcd,
519 	 .ident = "ESPRIMO Mobile M9410",
520 	 .matches = {
521 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
522 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
523 		},
524 	},
525 	/*
526 	 * Some machines report wrong key events on the acpi-bus, suppress
527 	 * key event reporting on these.  Note this is only intended to work
528 	 * around events which are plain wrong. In some cases we get double
529 	 * events, in this case acpi-video is considered the canonical source
530 	 * and the events from the other source should be filtered. E.g.
531 	 * by calling acpi_video_handles_brightness_key_presses() from the
532 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
533 	 */
534 	{
535 	 .callback = video_set_report_key_events,
536 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
537 	 .ident = "Dell Vostro V131",
538 	 .matches = {
539 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
540 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
541 		},
542 	},
543 	{
544 	 .callback = video_set_report_key_events,
545 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
546 	 .ident = "Dell Vostro 3350",
547 	 .matches = {
548 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
549 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
550 		},
551 	},
552 	/*
553 	 * Some machines change the brightness themselves when a brightness
554 	 * hotkey gets pressed, despite us telling them not to. In this case
555 	 * acpi_video_device_notify() should only call backlight_force_update(
556 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
557 	 */
558 	{
559 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
560 	 .callback = video_hw_changes_brightness,
561 	 .ident = "Packard Bell EasyNote MZ35",
562 	 .matches = {
563 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
564 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
565 		},
566 	},
567 	{}
568 };
569 
570 static unsigned long long
571 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
572 			      unsigned long long bqc_value)
573 {
574 	unsigned long long level;
575 
576 	if (device->brightness->flags._BQC_use_index) {
577 		/*
578 		 * _BQC returns an index that doesn't account for the first 2
579 		 * items with special meaning (see enum acpi_video_level_idx),
580 		 * so we need to compensate for that by offsetting ourselves
581 		 */
582 		if (device->brightness->flags._BCL_reversed)
583 			bqc_value = device->brightness->count -
584 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
585 
586 		level = device->brightness->levels[bqc_value +
587 						   ACPI_VIDEO_FIRST_LEVEL];
588 	} else {
589 		level = bqc_value;
590 	}
591 
592 	level += bqc_offset_aml_bug_workaround;
593 
594 	return level;
595 }
596 
597 static int
598 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
599 					unsigned long long *level, bool raw)
600 {
601 	acpi_status status = AE_OK;
602 	int i;
603 
604 	if (device->cap._BQC || device->cap._BCQ) {
605 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
606 
607 		status = acpi_evaluate_integer(device->dev->handle, buf,
608 						NULL, level);
609 		if (ACPI_SUCCESS(status)) {
610 			if (raw) {
611 				/*
612 				 * Caller has indicated he wants the raw
613 				 * value returned by _BQC, so don't furtherly
614 				 * mess with the value.
615 				 */
616 				return 0;
617 			}
618 
619 			*level = acpi_video_bqc_value_to_level(device, *level);
620 
621 			for (i = ACPI_VIDEO_FIRST_LEVEL;
622 			     i < device->brightness->count; i++)
623 				if (device->brightness->levels[i] == *level) {
624 					device->brightness->curr = *level;
625 					return 0;
626 				}
627 			/*
628 			 * BQC returned an invalid level.
629 			 * Stop using it.
630 			 */
631 			acpi_handle_info(device->dev->handle,
632 					 "%s returned an invalid level", buf);
633 			device->cap._BQC = device->cap._BCQ = 0;
634 		} else {
635 			/*
636 			 * Fixme:
637 			 * should we return an error or ignore this failure?
638 			 * dev->brightness->curr is a cached value which stores
639 			 * the correct current backlight level in most cases.
640 			 * ACPI video backlight still works w/ buggy _BQC.
641 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
642 			 */
643 			acpi_handle_info(device->dev->handle,
644 					 "%s evaluation failed", buf);
645 			device->cap._BQC = device->cap._BCQ = 0;
646 		}
647 	}
648 
649 	*level = device->brightness->curr;
650 	return 0;
651 }
652 
653 static int
654 acpi_video_device_EDID(struct acpi_video_device *device,
655 		       union acpi_object **edid, ssize_t length)
656 {
657 	int status;
658 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
659 	union acpi_object *obj;
660 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
661 	struct acpi_object_list args = { 1, &arg0 };
662 
663 
664 	*edid = NULL;
665 
666 	if (!device)
667 		return -ENODEV;
668 	if (length == 128)
669 		arg0.integer.value = 1;
670 	else if (length == 256)
671 		arg0.integer.value = 2;
672 	else
673 		return -EINVAL;
674 
675 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
676 	if (ACPI_FAILURE(status))
677 		return -ENODEV;
678 
679 	obj = buffer.pointer;
680 
681 	if (obj && obj->type == ACPI_TYPE_BUFFER)
682 		*edid = obj;
683 	else {
684 		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
685 		status = -EFAULT;
686 		kfree(obj);
687 	}
688 
689 	return status;
690 }
691 
692 /* bus */
693 
694 /*
695  *  Arg:
696  *	video		: video bus device pointer
697  *	bios_flag	:
698  *		0.	The system BIOS should NOT automatically switch(toggle)
699  *			the active display output.
700  *		1.	The system BIOS should automatically switch (toggle) the
701  *			active display output. No switch event.
702  *		2.	The _DGS value should be locked.
703  *		3.	The system BIOS should not automatically switch (toggle) the
704  *			active display output, but instead generate the display switch
705  *			event notify code.
706  *	lcd_flag	:
707  *		0.	The system BIOS should automatically control the brightness level
708  *			of the LCD when:
709  *			- the power changes from AC to DC (ACPI appendix B)
710  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
711  *		1.	The system BIOS should NOT automatically control the brightness
712  *			level of the LCD when:
713  *			- the power changes from AC to DC (ACPI appendix B)
714  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
715  *  Return Value:
716  *		-EINVAL	wrong arg.
717  */
718 
719 static int
720 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
721 {
722 	acpi_status status;
723 
724 	if (!video->cap._DOS)
725 		return 0;
726 
727 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
728 		return -EINVAL;
729 	video->dos_setting = (lcd_flag << 2) | bios_flag;
730 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
731 					    (lcd_flag << 2) | bios_flag);
732 	if (ACPI_FAILURE(status))
733 		return -EIO;
734 
735 	return 0;
736 }
737 
738 /*
739  * Simple comparison function used to sort backlight levels.
740  */
741 
742 static int
743 acpi_video_cmp_level(const void *a, const void *b)
744 {
745 	return *(int *)a - *(int *)b;
746 }
747 
748 /*
749  * Decides if _BQC/_BCQ for this system is usable
750  *
751  * We do this by changing the level first and then read out the current
752  * brightness level, if the value does not match, find out if it is using
753  * index. If not, clear the _BQC/_BCQ capability.
754  */
755 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
756 				int max_level, int current_level)
757 {
758 	struct acpi_video_device_brightness *br = device->brightness;
759 	int result;
760 	unsigned long long level;
761 	int test_level;
762 
763 	/* don't mess with existing known broken systems */
764 	if (bqc_offset_aml_bug_workaround)
765 		return 0;
766 
767 	/*
768 	 * Some systems always report current brightness level as maximum
769 	 * through _BQC, we need to test another value for them. However,
770 	 * there is a subtlety:
771 	 *
772 	 * If the _BCL package ordering is descending, the first level
773 	 * (br->levels[2]) is likely to be 0, and if the number of levels
774 	 * matches the number of steps, we might confuse a returned level to
775 	 * mean the index.
776 	 *
777 	 * For example:
778 	 *
779 	 *     current_level = max_level = 100
780 	 *     test_level = 0
781 	 *     returned level = 100
782 	 *
783 	 * In this case 100 means the level, not the index, and _BCM failed.
784 	 * Still, if the _BCL package ordering is descending, the index of
785 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
786 	 *
787 	 * This causes all _BQC calls to return bogus values causing weird
788 	 * behavior from the user's perspective.  For example:
789 	 *
790 	 * xbacklight -set 10; xbacklight -set 20;
791 	 *
792 	 * would flash to 90% and then slowly down to the desired level (20).
793 	 *
794 	 * The solution is simple; test anything other than the first level
795 	 * (e.g. 1).
796 	 */
797 	test_level = current_level == max_level
798 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
799 		: max_level;
800 
801 	result = acpi_video_device_lcd_set_level(device, test_level);
802 	if (result)
803 		return result;
804 
805 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
806 	if (result)
807 		return result;
808 
809 	if (level != test_level) {
810 		/* buggy _BQC found, need to find out if it uses index */
811 		if (level < br->count) {
812 			if (br->flags._BCL_reversed)
813 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
814 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
815 				br->flags._BQC_use_index = 1;
816 		}
817 
818 		if (!br->flags._BQC_use_index)
819 			device->cap._BQC = device->cap._BCQ = 0;
820 	}
821 
822 	return 0;
823 }
824 
825 int acpi_video_get_levels(struct acpi_device *device,
826 			  struct acpi_video_device_brightness **dev_br,
827 			  int *pmax_level)
828 {
829 	union acpi_object *obj = NULL;
830 	int i, max_level = 0, count = 0, level_ac_battery = 0;
831 	union acpi_object *o;
832 	struct acpi_video_device_brightness *br = NULL;
833 	int result = 0;
834 	u32 value;
835 
836 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
837 		acpi_handle_debug(device->handle,
838 				  "Could not query available LCD brightness level\n");
839 		result = -ENODEV;
840 		goto out;
841 	}
842 
843 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
844 		result = -EINVAL;
845 		goto out;
846 	}
847 
848 	br = kzalloc(sizeof(*br), GFP_KERNEL);
849 	if (!br) {
850 		result = -ENOMEM;
851 		goto out;
852 	}
853 
854 	/*
855 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
856 	 * in order to account for buggy BIOS which don't export the first two
857 	 * special levels (see below)
858 	 */
859 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
860 				   sizeof(*br->levels),
861 				   GFP_KERNEL);
862 	if (!br->levels) {
863 		result = -ENOMEM;
864 		goto out_free;
865 	}
866 
867 	for (i = 0; i < obj->package.count; i++) {
868 		o = (union acpi_object *)&obj->package.elements[i];
869 		if (o->type != ACPI_TYPE_INTEGER) {
870 			acpi_handle_info(device->handle, "Invalid data\n");
871 			continue;
872 		}
873 		value = (u32) o->integer.value;
874 		/* Skip duplicate entries */
875 		if (count > ACPI_VIDEO_FIRST_LEVEL
876 		    && br->levels[count - 1] == value)
877 			continue;
878 
879 		br->levels[count] = value;
880 
881 		if (br->levels[count] > max_level)
882 			max_level = br->levels[count];
883 		count++;
884 	}
885 
886 	/*
887 	 * some buggy BIOS don't export the levels
888 	 * when machine is on AC/Battery in _BCL package.
889 	 * In this case, the first two elements in _BCL packages
890 	 * are also supported brightness levels that OS should take care of.
891 	 */
892 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
893 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
894 			level_ac_battery++;
895 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
896 			level_ac_battery++;
897 	}
898 
899 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
900 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
901 		br->flags._BCL_no_ac_battery_levels = 1;
902 		for (i = (count - 1 + level_ac_battery);
903 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
904 			br->levels[i] = br->levels[i - level_ac_battery];
905 		count += level_ac_battery;
906 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
907 		acpi_handle_info(device->handle,
908 				 "Too many duplicates in _BCL package");
909 
910 	/* Check if the _BCL package is in a reversed order */
911 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
912 		br->flags._BCL_reversed = 1;
913 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
914 		     count - ACPI_VIDEO_FIRST_LEVEL,
915 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
916 		     acpi_video_cmp_level, NULL);
917 	} else if (max_level != br->levels[count - 1])
918 		acpi_handle_info(device->handle,
919 				 "Found unordered _BCL package");
920 
921 	br->count = count;
922 	*dev_br = br;
923 	if (pmax_level)
924 		*pmax_level = max_level;
925 
926 out:
927 	kfree(obj);
928 	return result;
929 out_free:
930 	kfree(br);
931 	goto out;
932 }
933 EXPORT_SYMBOL(acpi_video_get_levels);
934 
935 /*
936  *  Arg:
937  *	device	: video output device (LCD, CRT, ..)
938  *
939  *  Return Value:
940  *	Maximum brightness level
941  *
942  *  Allocate and initialize device->brightness.
943  */
944 
945 static int
946 acpi_video_init_brightness(struct acpi_video_device *device)
947 {
948 	int i, max_level = 0;
949 	unsigned long long level, level_old;
950 	struct acpi_video_device_brightness *br = NULL;
951 	int result;
952 
953 	result = acpi_video_get_levels(device->dev, &br, &max_level);
954 	if (result)
955 		return result;
956 	device->brightness = br;
957 
958 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
959 	br->curr = level = max_level;
960 
961 	if (!device->cap._BQC)
962 		goto set_level;
963 
964 	result = acpi_video_device_lcd_get_level_current(device,
965 							 &level_old, true);
966 	if (result)
967 		goto out_free_levels;
968 
969 	result = acpi_video_bqc_quirk(device, max_level, level_old);
970 	if (result)
971 		goto out_free_levels;
972 	/*
973 	 * cap._BQC may get cleared due to _BQC is found to be broken
974 	 * in acpi_video_bqc_quirk, so check again here.
975 	 */
976 	if (!device->cap._BQC)
977 		goto set_level;
978 
979 	level = acpi_video_bqc_value_to_level(device, level_old);
980 	/*
981 	 * On some buggy laptops, _BQC returns an uninitialized
982 	 * value when invoked for the first time, i.e.
983 	 * level_old is invalid (no matter whether it's a level
984 	 * or an index). Set the backlight to max_level in this case.
985 	 */
986 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
987 		if (level == br->levels[i])
988 			break;
989 	if (i == br->count || !level)
990 		level = max_level;
991 
992 set_level:
993 	result = acpi_video_device_lcd_set_level(device, level);
994 	if (result)
995 		goto out_free_levels;
996 
997 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
998 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
999 
1000 	return 0;
1001 
1002 out_free_levels:
1003 	kfree(br->levels);
1004 	kfree(br);
1005 	device->brightness = NULL;
1006 	return result;
1007 }
1008 
1009 /*
1010  *  Arg:
1011  *	device	: video output device (LCD, CRT, ..)
1012  *
1013  *  Return Value:
1014  *	None
1015  *
1016  *  Find out all required AML methods defined under the output
1017  *  device.
1018  */
1019 
1020 static void acpi_video_device_find_cap(struct acpi_video_device *device)
1021 {
1022 	if (acpi_has_method(device->dev->handle, "_ADR"))
1023 		device->cap._ADR = 1;
1024 	if (acpi_has_method(device->dev->handle, "_BCL"))
1025 		device->cap._BCL = 1;
1026 	if (acpi_has_method(device->dev->handle, "_BCM"))
1027 		device->cap._BCM = 1;
1028 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1029 		device->cap._BQC = 1;
1030 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1031 		acpi_handle_info(device->dev->handle,
1032 				 "_BCQ is used instead of _BQC\n");
1033 		device->cap._BCQ = 1;
1034 	}
1035 
1036 	if (acpi_has_method(device->dev->handle, "_DDC"))
1037 		device->cap._DDC = 1;
1038 }
1039 
1040 /*
1041  *  Arg:
1042  *	device	: video output device (VGA)
1043  *
1044  *  Return Value:
1045  *	None
1046  *
1047  *  Find out all required AML methods defined under the video bus device.
1048  */
1049 
1050 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1051 {
1052 	if (acpi_has_method(video->device->handle, "_DOS"))
1053 		video->cap._DOS = 1;
1054 	if (acpi_has_method(video->device->handle, "_DOD"))
1055 		video->cap._DOD = 1;
1056 	if (acpi_has_method(video->device->handle, "_ROM"))
1057 		video->cap._ROM = 1;
1058 	if (acpi_has_method(video->device->handle, "_GPD"))
1059 		video->cap._GPD = 1;
1060 	if (acpi_has_method(video->device->handle, "_SPD"))
1061 		video->cap._SPD = 1;
1062 	if (acpi_has_method(video->device->handle, "_VPO"))
1063 		video->cap._VPO = 1;
1064 }
1065 
1066 /*
1067  * Check whether the video bus device has required AML method to
1068  * support the desired features
1069  */
1070 
1071 static int acpi_video_bus_check(struct acpi_video_bus *video)
1072 {
1073 	acpi_status status = -ENOENT;
1074 	struct pci_dev *dev;
1075 
1076 	if (!video)
1077 		return -EINVAL;
1078 
1079 	dev = acpi_get_pci_dev(video->device->handle);
1080 	if (!dev)
1081 		return -ENODEV;
1082 	pci_dev_put(dev);
1083 
1084 	/*
1085 	 * Since there is no HID, CID and so on for VGA driver, we have
1086 	 * to check well known required nodes.
1087 	 */
1088 
1089 	/* Does this device support video switching? */
1090 	if (video->cap._DOS || video->cap._DOD) {
1091 		if (!video->cap._DOS) {
1092 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1093 				acpi_device_bid(video->device));
1094 		}
1095 		video->flags.multihead = 1;
1096 		status = 0;
1097 	}
1098 
1099 	/* Does this device support retrieving a video ROM? */
1100 	if (video->cap._ROM) {
1101 		video->flags.rom = 1;
1102 		status = 0;
1103 	}
1104 
1105 	/* Does this device support configuring which video device to POST? */
1106 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1107 		video->flags.post = 1;
1108 		status = 0;
1109 	}
1110 
1111 	return status;
1112 }
1113 
1114 /*
1115  * --------------------------------------------------------------------------
1116  *                               Driver Interface
1117  * --------------------------------------------------------------------------
1118  */
1119 
1120 /* device interface */
1121 static struct acpi_video_device_attrib *
1122 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1123 {
1124 	struct acpi_video_enumerated_device *ids;
1125 	int i;
1126 
1127 	for (i = 0; i < video->attached_count; i++) {
1128 		ids = &video->attached_array[i];
1129 		if ((ids->value.int_val & 0xffff) == device_id)
1130 			return &ids->value.attrib;
1131 	}
1132 
1133 	return NULL;
1134 }
1135 
1136 static int
1137 acpi_video_get_device_type(struct acpi_video_bus *video,
1138 			   unsigned long device_id)
1139 {
1140 	struct acpi_video_enumerated_device *ids;
1141 	int i;
1142 
1143 	for (i = 0; i < video->attached_count; i++) {
1144 		ids = &video->attached_array[i];
1145 		if ((ids->value.int_val & 0xffff) == device_id)
1146 			return ids->value.int_val;
1147 	}
1148 
1149 	return 0;
1150 }
1151 
1152 static int
1153 acpi_video_bus_get_one_device(struct acpi_device *device,
1154 			      struct acpi_video_bus *video)
1155 {
1156 	unsigned long long device_id;
1157 	int status, device_type;
1158 	struct acpi_video_device *data;
1159 	struct acpi_video_device_attrib *attribute;
1160 
1161 	status =
1162 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1163 	/* Some device omits _ADR, we skip them instead of fail */
1164 	if (ACPI_FAILURE(status))
1165 		return 0;
1166 
1167 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1168 	if (!data)
1169 		return -ENOMEM;
1170 
1171 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1172 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1173 	device->driver_data = data;
1174 
1175 	data->device_id = device_id;
1176 	data->video = video;
1177 	data->dev = device;
1178 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1179 			  acpi_video_switch_brightness);
1180 
1181 	attribute = acpi_video_get_device_attr(video, device_id);
1182 
1183 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1184 		switch (attribute->display_type) {
1185 		case ACPI_VIDEO_DISPLAY_CRT:
1186 			data->flags.crt = 1;
1187 			break;
1188 		case ACPI_VIDEO_DISPLAY_TV:
1189 			data->flags.tvout = 1;
1190 			break;
1191 		case ACPI_VIDEO_DISPLAY_DVI:
1192 			data->flags.dvi = 1;
1193 			break;
1194 		case ACPI_VIDEO_DISPLAY_LCD:
1195 			data->flags.lcd = 1;
1196 			break;
1197 		default:
1198 			data->flags.unknown = 1;
1199 			break;
1200 		}
1201 		if (attribute->bios_can_detect)
1202 			data->flags.bios = 1;
1203 	} else {
1204 		/* Check for legacy IDs */
1205 		device_type = acpi_video_get_device_type(video, device_id);
1206 		/* Ignore bits 16 and 18-20 */
1207 		switch (device_type & 0xffe2ffff) {
1208 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1209 			data->flags.crt = 1;
1210 			break;
1211 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1212 			data->flags.lcd = 1;
1213 			break;
1214 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1215 			data->flags.tvout = 1;
1216 			break;
1217 		default:
1218 			data->flags.unknown = 1;
1219 		}
1220 	}
1221 
1222 	acpi_video_device_bind(video, data);
1223 	acpi_video_device_find_cap(data);
1224 
1225 	mutex_lock(&video->device_list_lock);
1226 	list_add_tail(&data->entry, &video->video_device_list);
1227 	mutex_unlock(&video->device_list_lock);
1228 
1229 	return status;
1230 }
1231 
1232 /*
1233  *  Arg:
1234  *	video	: video bus device
1235  *
1236  *  Return:
1237  *	none
1238  *
1239  *  Enumerate the video device list of the video bus,
1240  *  bind the ids with the corresponding video devices
1241  *  under the video bus.
1242  */
1243 
1244 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1245 {
1246 	struct acpi_video_device *dev;
1247 
1248 	mutex_lock(&video->device_list_lock);
1249 
1250 	list_for_each_entry(dev, &video->video_device_list, entry)
1251 		acpi_video_device_bind(video, dev);
1252 
1253 	mutex_unlock(&video->device_list_lock);
1254 }
1255 
1256 /*
1257  *  Arg:
1258  *	video	: video bus device
1259  *	device	: video output device under the video
1260  *		bus
1261  *
1262  *  Return:
1263  *	none
1264  *
1265  *  Bind the ids with the corresponding video devices
1266  *  under the video bus.
1267  */
1268 
1269 static void
1270 acpi_video_device_bind(struct acpi_video_bus *video,
1271 		       struct acpi_video_device *device)
1272 {
1273 	struct acpi_video_enumerated_device *ids;
1274 	int i;
1275 
1276 	for (i = 0; i < video->attached_count; i++) {
1277 		ids = &video->attached_array[i];
1278 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1279 			ids->bind_info = device;
1280 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1281 					  __func__, i);
1282 		}
1283 	}
1284 }
1285 
1286 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1287 {
1288 	struct acpi_video_bus *video = device->video;
1289 	int i;
1290 
1291 	/*
1292 	 * If we have a broken _DOD or we have more than 8 output devices
1293 	 * under the graphics controller node that we can't proper deal with
1294 	 * in the operation region code currently, no need to test.
1295 	 */
1296 	if (!video->attached_count || video->child_count > 8)
1297 		return true;
1298 
1299 	for (i = 0; i < video->attached_count; i++) {
1300 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1301 		    (device->device_id & 0xfff))
1302 			return true;
1303 	}
1304 
1305 	return false;
1306 }
1307 
1308 /*
1309  *  Arg:
1310  *	video	: video bus device
1311  *
1312  *  Return:
1313  *	< 0	: error
1314  *
1315  *  Call _DOD to enumerate all devices attached to display adapter
1316  *
1317  */
1318 
1319 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1320 {
1321 	int status;
1322 	int count;
1323 	int i;
1324 	struct acpi_video_enumerated_device *active_list;
1325 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1326 	union acpi_object *dod = NULL;
1327 	union acpi_object *obj;
1328 
1329 	if (!video->cap._DOD)
1330 		return AE_NOT_EXIST;
1331 
1332 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1333 	if (ACPI_FAILURE(status)) {
1334 		acpi_handle_info(video->device->handle,
1335 				 "_DOD evaluation failed: %s\n",
1336 				 acpi_format_exception(status));
1337 		return status;
1338 	}
1339 
1340 	dod = buffer.pointer;
1341 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1342 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1343 		status = -EFAULT;
1344 		goto out;
1345 	}
1346 
1347 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1348 			  dod->package.count);
1349 
1350 	active_list = kcalloc(1 + dod->package.count,
1351 			      sizeof(struct acpi_video_enumerated_device),
1352 			      GFP_KERNEL);
1353 	if (!active_list) {
1354 		status = -ENOMEM;
1355 		goto out;
1356 	}
1357 
1358 	count = 0;
1359 	for (i = 0; i < dod->package.count; i++) {
1360 		obj = &dod->package.elements[i];
1361 
1362 		if (obj->type != ACPI_TYPE_INTEGER) {
1363 			acpi_handle_info(video->device->handle,
1364 					 "Invalid _DOD data in element %d\n", i);
1365 			continue;
1366 		}
1367 
1368 		active_list[count].value.int_val = obj->integer.value;
1369 		active_list[count].bind_info = NULL;
1370 
1371 		acpi_handle_debug(video->device->handle,
1372 				  "_DOD element[%d] = %d\n", i,
1373 				  (int)obj->integer.value);
1374 
1375 		count++;
1376 	}
1377 
1378 	kfree(video->attached_array);
1379 
1380 	video->attached_array = active_list;
1381 	video->attached_count = count;
1382 
1383 out:
1384 	kfree(buffer.pointer);
1385 	return status;
1386 }
1387 
1388 static int
1389 acpi_video_get_next_level(struct acpi_video_device *device,
1390 			  u32 level_current, u32 event)
1391 {
1392 	int min, max, min_above, max_below, i, l, delta = 255;
1393 	max = max_below = 0;
1394 	min = min_above = 255;
1395 	/* Find closest level to level_current */
1396 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1397 		l = device->brightness->levels[i];
1398 		if (abs(l - level_current) < abs(delta)) {
1399 			delta = l - level_current;
1400 			if (!delta)
1401 				break;
1402 		}
1403 	}
1404 	/* Adjust level_current to closest available level */
1405 	level_current += delta;
1406 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1407 		l = device->brightness->levels[i];
1408 		if (l < min)
1409 			min = l;
1410 		if (l > max)
1411 			max = l;
1412 		if (l < min_above && l > level_current)
1413 			min_above = l;
1414 		if (l > max_below && l < level_current)
1415 			max_below = l;
1416 	}
1417 
1418 	switch (event) {
1419 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1420 		return (level_current < max) ? min_above : min;
1421 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1422 		return (level_current < max) ? min_above : max;
1423 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1424 		return (level_current > min) ? max_below : min;
1425 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1426 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1427 		return 0;
1428 	default:
1429 		return level_current;
1430 	}
1431 }
1432 
1433 static void
1434 acpi_video_switch_brightness(struct work_struct *work)
1435 {
1436 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1437 			     struct acpi_video_device, switch_brightness_work);
1438 	unsigned long long level_current, level_next;
1439 	int event = device->switch_brightness_event;
1440 	int result = -EINVAL;
1441 
1442 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1443 	if (!device->backlight)
1444 		return;
1445 
1446 	if (!device->brightness)
1447 		goto out;
1448 
1449 	result = acpi_video_device_lcd_get_level_current(device,
1450 							 &level_current,
1451 							 false);
1452 	if (result)
1453 		goto out;
1454 
1455 	level_next = acpi_video_get_next_level(device, level_current, event);
1456 
1457 	result = acpi_video_device_lcd_set_level(device, level_next);
1458 
1459 	if (!result)
1460 		backlight_force_update(device->backlight,
1461 				       BACKLIGHT_UPDATE_HOTKEY);
1462 
1463 out:
1464 	if (result)
1465 		acpi_handle_info(device->dev->handle,
1466 				 "Failed to switch brightness\n");
1467 }
1468 
1469 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1470 			void **edid)
1471 {
1472 	struct acpi_video_bus *video;
1473 	struct acpi_video_device *video_device;
1474 	union acpi_object *buffer = NULL;
1475 	acpi_status status;
1476 	int i, length;
1477 
1478 	if (!device || !acpi_driver_data(device))
1479 		return -EINVAL;
1480 
1481 	video = acpi_driver_data(device);
1482 
1483 	for (i = 0; i < video->attached_count; i++) {
1484 		video_device = video->attached_array[i].bind_info;
1485 		length = 256;
1486 
1487 		if (!video_device)
1488 			continue;
1489 
1490 		if (!video_device->cap._DDC)
1491 			continue;
1492 
1493 		if (type) {
1494 			switch (type) {
1495 			case ACPI_VIDEO_DISPLAY_CRT:
1496 				if (!video_device->flags.crt)
1497 					continue;
1498 				break;
1499 			case ACPI_VIDEO_DISPLAY_TV:
1500 				if (!video_device->flags.tvout)
1501 					continue;
1502 				break;
1503 			case ACPI_VIDEO_DISPLAY_DVI:
1504 				if (!video_device->flags.dvi)
1505 					continue;
1506 				break;
1507 			case ACPI_VIDEO_DISPLAY_LCD:
1508 				if (!video_device->flags.lcd)
1509 					continue;
1510 				break;
1511 			}
1512 		} else if (video_device->device_id != device_id) {
1513 			continue;
1514 		}
1515 
1516 		status = acpi_video_device_EDID(video_device, &buffer, length);
1517 
1518 		if (ACPI_FAILURE(status) || !buffer ||
1519 		    buffer->type != ACPI_TYPE_BUFFER) {
1520 			length = 128;
1521 			status = acpi_video_device_EDID(video_device, &buffer,
1522 							length);
1523 			if (ACPI_FAILURE(status) || !buffer ||
1524 			    buffer->type != ACPI_TYPE_BUFFER) {
1525 				continue;
1526 			}
1527 		}
1528 
1529 		*edid = buffer->buffer.pointer;
1530 		return length;
1531 	}
1532 
1533 	return -ENODEV;
1534 }
1535 EXPORT_SYMBOL(acpi_video_get_edid);
1536 
1537 static int
1538 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1539 			   struct acpi_device *device)
1540 {
1541 	int status = 0;
1542 	struct acpi_device *dev;
1543 
1544 	/*
1545 	 * There are systems where video module known to work fine regardless
1546 	 * of broken _DOD and ignoring returned value here doesn't cause
1547 	 * any issues later.
1548 	 */
1549 	acpi_video_device_enumerate(video);
1550 
1551 	list_for_each_entry(dev, &device->children, node) {
1552 
1553 		status = acpi_video_bus_get_one_device(dev, video);
1554 		if (status) {
1555 			dev_err(&dev->dev, "Can't attach device\n");
1556 			break;
1557 		}
1558 		video->child_count++;
1559 	}
1560 	return status;
1561 }
1562 
1563 /* acpi_video interface */
1564 
1565 /*
1566  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1567  * perform any automatic brightness change on receiving a notification.
1568  */
1569 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1570 {
1571 	return acpi_video_bus_DOS(video, 0,
1572 				  acpi_osi_is_win8() ? 1 : 0);
1573 }
1574 
1575 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1576 {
1577 	return acpi_video_bus_DOS(video, 0,
1578 				  acpi_osi_is_win8() ? 0 : 1);
1579 }
1580 
1581 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1582 {
1583 	struct acpi_video_bus *video = acpi_driver_data(device);
1584 	struct input_dev *input;
1585 	int keycode = 0;
1586 
1587 	if (!video || !video->input)
1588 		return;
1589 
1590 	input = video->input;
1591 
1592 	switch (event) {
1593 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1594 					 * most likely via hotkey. */
1595 		keycode = KEY_SWITCHVIDEOMODE;
1596 		break;
1597 
1598 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1599 					 * connector. */
1600 		acpi_video_device_enumerate(video);
1601 		acpi_video_device_rebind(video);
1602 		keycode = KEY_SWITCHVIDEOMODE;
1603 		break;
1604 
1605 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1606 		keycode = KEY_SWITCHVIDEOMODE;
1607 		break;
1608 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1609 		keycode = KEY_VIDEO_NEXT;
1610 		break;
1611 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1612 		keycode = KEY_VIDEO_PREV;
1613 		break;
1614 
1615 	default:
1616 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1617 				  event);
1618 		break;
1619 	}
1620 
1621 	if (acpi_notifier_call_chain(device, event, 0))
1622 		/* Something vetoed the keypress. */
1623 		keycode = 0;
1624 
1625 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1626 		input_report_key(input, keycode, 1);
1627 		input_sync(input);
1628 		input_report_key(input, keycode, 0);
1629 		input_sync(input);
1630 	}
1631 }
1632 
1633 static void brightness_switch_event(struct acpi_video_device *video_device,
1634 				    u32 event)
1635 {
1636 	if (!brightness_switch_enabled)
1637 		return;
1638 
1639 	video_device->switch_brightness_event = event;
1640 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1641 }
1642 
1643 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1644 {
1645 	struct acpi_video_device *video_device = data;
1646 	struct acpi_device *device = NULL;
1647 	struct acpi_video_bus *bus;
1648 	struct input_dev *input;
1649 	int keycode = 0;
1650 
1651 	if (!video_device)
1652 		return;
1653 
1654 	device = video_device->dev;
1655 	bus = video_device->video;
1656 	input = bus->input;
1657 
1658 	if (hw_changes_brightness > 0) {
1659 		if (video_device->backlight)
1660 			backlight_force_update(video_device->backlight,
1661 					       BACKLIGHT_UPDATE_HOTKEY);
1662 		acpi_notifier_call_chain(device, event, 0);
1663 		return;
1664 	}
1665 
1666 	switch (event) {
1667 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1668 		brightness_switch_event(video_device, event);
1669 		keycode = KEY_BRIGHTNESS_CYCLE;
1670 		break;
1671 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1672 		brightness_switch_event(video_device, event);
1673 		keycode = KEY_BRIGHTNESSUP;
1674 		break;
1675 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1676 		brightness_switch_event(video_device, event);
1677 		keycode = KEY_BRIGHTNESSDOWN;
1678 		break;
1679 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1680 		brightness_switch_event(video_device, event);
1681 		keycode = KEY_BRIGHTNESS_ZERO;
1682 		break;
1683 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1684 		brightness_switch_event(video_device, event);
1685 		keycode = KEY_DISPLAY_OFF;
1686 		break;
1687 	default:
1688 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1689 		break;
1690 	}
1691 
1692 	acpi_notifier_call_chain(device, event, 0);
1693 
1694 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1695 		input_report_key(input, keycode, 1);
1696 		input_sync(input);
1697 		input_report_key(input, keycode, 0);
1698 		input_sync(input);
1699 	}
1700 }
1701 
1702 static int acpi_video_resume(struct notifier_block *nb,
1703 				unsigned long val, void *ign)
1704 {
1705 	struct acpi_video_bus *video;
1706 	struct acpi_video_device *video_device;
1707 	int i;
1708 
1709 	switch (val) {
1710 	case PM_POST_HIBERNATION:
1711 	case PM_POST_SUSPEND:
1712 	case PM_POST_RESTORE:
1713 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1714 
1715 		dev_info(&video->device->dev, "Restoring backlight state\n");
1716 
1717 		for (i = 0; i < video->attached_count; i++) {
1718 			video_device = video->attached_array[i].bind_info;
1719 			if (video_device && video_device->brightness)
1720 				acpi_video_device_lcd_set_level(video_device,
1721 						video_device->brightness->curr);
1722 		}
1723 
1724 		return NOTIFY_OK;
1725 	}
1726 	return NOTIFY_DONE;
1727 }
1728 
1729 static acpi_status
1730 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1731 			void **return_value)
1732 {
1733 	struct acpi_device *device = context;
1734 	struct acpi_device *sibling;
1735 
1736 	if (handle == device->handle)
1737 		return AE_CTRL_TERMINATE;
1738 
1739 	sibling = acpi_fetch_acpi_dev(handle);
1740 	if (!sibling)
1741 		return AE_OK;
1742 
1743 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1744 			return AE_ALREADY_EXISTS;
1745 
1746 	return AE_OK;
1747 }
1748 
1749 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1750 {
1751 	struct backlight_properties props;
1752 	struct pci_dev *pdev;
1753 	acpi_handle acpi_parent;
1754 	struct device *parent = NULL;
1755 	int result;
1756 	static int count;
1757 	char *name;
1758 
1759 	result = acpi_video_init_brightness(device);
1760 	if (result)
1761 		return;
1762 
1763 	if (disable_backlight_sysfs_if > 0)
1764 		return;
1765 
1766 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1767 	if (!name)
1768 		return;
1769 	count++;
1770 
1771 	acpi_get_parent(device->dev->handle, &acpi_parent);
1772 
1773 	pdev = acpi_get_pci_dev(acpi_parent);
1774 	if (pdev) {
1775 		parent = &pdev->dev;
1776 		pci_dev_put(pdev);
1777 	}
1778 
1779 	memset(&props, 0, sizeof(struct backlight_properties));
1780 	props.type = BACKLIGHT_FIRMWARE;
1781 	props.max_brightness =
1782 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1783 	device->backlight = backlight_device_register(name,
1784 						      parent,
1785 						      device,
1786 						      &acpi_backlight_ops,
1787 						      &props);
1788 	kfree(name);
1789 	if (IS_ERR(device->backlight)) {
1790 		device->backlight = NULL;
1791 		return;
1792 	}
1793 
1794 	/*
1795 	 * Save current brightness level in case we have to restore it
1796 	 * before acpi_video_device_lcd_set_level() is called next time.
1797 	 */
1798 	device->backlight->props.brightness =
1799 			acpi_video_get_brightness(device->backlight);
1800 
1801 	device->cooling_dev = thermal_cooling_device_register("LCD",
1802 				device->dev, &video_cooling_ops);
1803 	if (IS_ERR(device->cooling_dev)) {
1804 		/*
1805 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1806 		 * Also, why the hell we are returning early and not attempt to
1807 		 * register video output if cooling device registration failed?
1808 		 * -- dtor
1809 		 */
1810 		device->cooling_dev = NULL;
1811 		return;
1812 	}
1813 
1814 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1815 		 device->cooling_dev->id);
1816 	result = sysfs_create_link(&device->dev->dev.kobj,
1817 			&device->cooling_dev->device.kobj,
1818 			"thermal_cooling");
1819 	if (result)
1820 		pr_info("sysfs link creation failed\n");
1821 
1822 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1823 			&device->dev->dev.kobj, "device");
1824 	if (result)
1825 		pr_info("Reverse sysfs link creation failed\n");
1826 }
1827 
1828 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1829 {
1830 	struct acpi_video_device *dev;
1831 	union acpi_object *levels;
1832 
1833 	mutex_lock(&video->device_list_lock);
1834 	list_for_each_entry(dev, &video->video_device_list, entry) {
1835 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1836 			kfree(levels);
1837 	}
1838 	mutex_unlock(&video->device_list_lock);
1839 }
1840 
1841 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1842 {
1843 	/*
1844 	 * Do not create backlight device for video output
1845 	 * device that is not in the enumerated list.
1846 	 */
1847 	if (!acpi_video_device_in_dod(dev)) {
1848 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1849 		return false;
1850 	}
1851 
1852 	if (only_lcd)
1853 		return dev->flags.lcd;
1854 	return true;
1855 }
1856 
1857 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1858 {
1859 	struct acpi_video_device *dev;
1860 
1861 	if (video->backlight_registered)
1862 		return 0;
1863 
1864 	acpi_video_run_bcl_for_osi(video);
1865 
1866 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1867 		return 0;
1868 
1869 	mutex_lock(&video->device_list_lock);
1870 	list_for_each_entry(dev, &video->video_device_list, entry) {
1871 		if (acpi_video_should_register_backlight(dev))
1872 			acpi_video_dev_register_backlight(dev);
1873 	}
1874 	mutex_unlock(&video->device_list_lock);
1875 
1876 	video->backlight_registered = true;
1877 
1878 	video->pm_nb.notifier_call = acpi_video_resume;
1879 	video->pm_nb.priority = 0;
1880 	return register_pm_notifier(&video->pm_nb);
1881 }
1882 
1883 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1884 {
1885 	if (device->backlight) {
1886 		backlight_device_unregister(device->backlight);
1887 		device->backlight = NULL;
1888 	}
1889 	if (device->brightness) {
1890 		kfree(device->brightness->levels);
1891 		kfree(device->brightness);
1892 		device->brightness = NULL;
1893 	}
1894 	if (device->cooling_dev) {
1895 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1896 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1897 		thermal_cooling_device_unregister(device->cooling_dev);
1898 		device->cooling_dev = NULL;
1899 	}
1900 }
1901 
1902 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1903 {
1904 	struct acpi_video_device *dev;
1905 	int error;
1906 
1907 	if (!video->backlight_registered)
1908 		return 0;
1909 
1910 	error = unregister_pm_notifier(&video->pm_nb);
1911 
1912 	mutex_lock(&video->device_list_lock);
1913 	list_for_each_entry(dev, &video->video_device_list, entry)
1914 		acpi_video_dev_unregister_backlight(dev);
1915 	mutex_unlock(&video->device_list_lock);
1916 
1917 	video->backlight_registered = false;
1918 
1919 	return error;
1920 }
1921 
1922 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1923 {
1924 	acpi_status status;
1925 	struct acpi_device *adev = device->dev;
1926 
1927 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1928 					     acpi_video_device_notify, device);
1929 	if (ACPI_FAILURE(status))
1930 		dev_err(&adev->dev, "Error installing notify handler\n");
1931 	else
1932 		device->flags.notify = 1;
1933 }
1934 
1935 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1936 {
1937 	struct input_dev *input;
1938 	struct acpi_video_device *dev;
1939 	int error;
1940 
1941 	video->input = input = input_allocate_device();
1942 	if (!input) {
1943 		error = -ENOMEM;
1944 		goto out;
1945 	}
1946 
1947 	error = acpi_video_bus_start_devices(video);
1948 	if (error)
1949 		goto err_free_input;
1950 
1951 	snprintf(video->phys, sizeof(video->phys),
1952 			"%s/video/input0", acpi_device_hid(video->device));
1953 
1954 	input->name = acpi_device_name(video->device);
1955 	input->phys = video->phys;
1956 	input->id.bustype = BUS_HOST;
1957 	input->id.product = 0x06;
1958 	input->dev.parent = &video->device->dev;
1959 	input->evbit[0] = BIT(EV_KEY);
1960 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1961 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1962 	set_bit(KEY_VIDEO_PREV, input->keybit);
1963 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1964 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1965 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1966 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1967 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1968 
1969 	error = input_register_device(input);
1970 	if (error)
1971 		goto err_stop_dev;
1972 
1973 	mutex_lock(&video->device_list_lock);
1974 	list_for_each_entry(dev, &video->video_device_list, entry)
1975 		acpi_video_dev_add_notify_handler(dev);
1976 	mutex_unlock(&video->device_list_lock);
1977 
1978 	return 0;
1979 
1980 err_stop_dev:
1981 	acpi_video_bus_stop_devices(video);
1982 err_free_input:
1983 	input_free_device(input);
1984 	video->input = NULL;
1985 out:
1986 	return error;
1987 }
1988 
1989 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1990 {
1991 	if (dev->flags.notify) {
1992 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1993 					   acpi_video_device_notify);
1994 		dev->flags.notify = 0;
1995 	}
1996 }
1997 
1998 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1999 {
2000 	struct acpi_video_device *dev;
2001 
2002 	mutex_lock(&video->device_list_lock);
2003 	list_for_each_entry(dev, &video->video_device_list, entry)
2004 		acpi_video_dev_remove_notify_handler(dev);
2005 	mutex_unlock(&video->device_list_lock);
2006 
2007 	acpi_video_bus_stop_devices(video);
2008 	input_unregister_device(video->input);
2009 	video->input = NULL;
2010 }
2011 
2012 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2013 {
2014 	struct acpi_video_device *dev, *next;
2015 
2016 	mutex_lock(&video->device_list_lock);
2017 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2018 		list_del(&dev->entry);
2019 		kfree(dev);
2020 	}
2021 	mutex_unlock(&video->device_list_lock);
2022 
2023 	return 0;
2024 }
2025 
2026 static int instance;
2027 
2028 static int acpi_video_bus_add(struct acpi_device *device)
2029 {
2030 	struct acpi_video_bus *video;
2031 	int error;
2032 	acpi_status status;
2033 
2034 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2035 				device->parent->handle, 1,
2036 				acpi_video_bus_match, NULL,
2037 				device, NULL);
2038 	if (status == AE_ALREADY_EXISTS) {
2039 		pr_info(FW_BUG
2040 			"Duplicate ACPI video bus devices for the"
2041 			" same VGA controller, please try module "
2042 			"parameter \"video.allow_duplicates=1\""
2043 			"if the current driver doesn't work.\n");
2044 		if (!allow_duplicates)
2045 			return -ENODEV;
2046 	}
2047 
2048 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2049 	if (!video)
2050 		return -ENOMEM;
2051 
2052 	/* a hack to fix the duplicate name "VID" problem on T61 */
2053 	if (!strcmp(device->pnp.bus_id, "VID")) {
2054 		if (instance)
2055 			device->pnp.bus_id[3] = '0' + instance;
2056 		instance++;
2057 	}
2058 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2059 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2060 		if (instance)
2061 			device->pnp.bus_id[3] = '0' + instance;
2062 		instance++;
2063 	}
2064 
2065 	video->device = device;
2066 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2067 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2068 	device->driver_data = video;
2069 
2070 	acpi_video_bus_find_cap(video);
2071 	error = acpi_video_bus_check(video);
2072 	if (error)
2073 		goto err_free_video;
2074 
2075 	mutex_init(&video->device_list_lock);
2076 	INIT_LIST_HEAD(&video->video_device_list);
2077 
2078 	error = acpi_video_bus_get_devices(video, device);
2079 	if (error)
2080 		goto err_put_video;
2081 
2082 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2083 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2084 	       video->flags.multihead ? "yes" : "no",
2085 	       video->flags.rom ? "yes" : "no",
2086 	       video->flags.post ? "yes" : "no");
2087 	mutex_lock(&video_list_lock);
2088 	list_add_tail(&video->entry, &video_bus_head);
2089 	mutex_unlock(&video_list_lock);
2090 
2091 	acpi_video_bus_register_backlight(video);
2092 	acpi_video_bus_add_notify_handler(video);
2093 
2094 	return 0;
2095 
2096 err_put_video:
2097 	acpi_video_bus_put_devices(video);
2098 	kfree(video->attached_array);
2099 err_free_video:
2100 	kfree(video);
2101 	device->driver_data = NULL;
2102 
2103 	return error;
2104 }
2105 
2106 static int acpi_video_bus_remove(struct acpi_device *device)
2107 {
2108 	struct acpi_video_bus *video = NULL;
2109 
2110 
2111 	if (!device || !acpi_driver_data(device))
2112 		return -EINVAL;
2113 
2114 	video = acpi_driver_data(device);
2115 
2116 	acpi_video_bus_remove_notify_handler(video);
2117 	acpi_video_bus_unregister_backlight(video);
2118 	acpi_video_bus_put_devices(video);
2119 
2120 	mutex_lock(&video_list_lock);
2121 	list_del(&video->entry);
2122 	mutex_unlock(&video_list_lock);
2123 
2124 	kfree(video->attached_array);
2125 	kfree(video);
2126 
2127 	return 0;
2128 }
2129 
2130 static int __init is_i740(struct pci_dev *dev)
2131 {
2132 	if (dev->device == 0x00D1)
2133 		return 1;
2134 	if (dev->device == 0x7000)
2135 		return 1;
2136 	return 0;
2137 }
2138 
2139 static int __init intel_opregion_present(void)
2140 {
2141 	int opregion = 0;
2142 	struct pci_dev *dev = NULL;
2143 	u32 address;
2144 
2145 	for_each_pci_dev(dev) {
2146 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2147 			continue;
2148 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2149 			continue;
2150 		/* We don't want to poke around undefined i740 registers */
2151 		if (is_i740(dev))
2152 			continue;
2153 		pci_read_config_dword(dev, 0xfc, &address);
2154 		if (!address)
2155 			continue;
2156 		opregion = 1;
2157 	}
2158 	return opregion;
2159 }
2160 
2161 /* Check if the chassis-type indicates there is no builtin LCD panel */
2162 static bool dmi_is_desktop(void)
2163 {
2164 	const char *chassis_type;
2165 	unsigned long type;
2166 
2167 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2168 	if (!chassis_type)
2169 		return false;
2170 
2171 	if (kstrtoul(chassis_type, 10, &type) != 0)
2172 		return false;
2173 
2174 	switch (type) {
2175 	case 0x03: /* Desktop */
2176 	case 0x04: /* Low Profile Desktop */
2177 	case 0x05: /* Pizza Box */
2178 	case 0x06: /* Mini Tower */
2179 	case 0x07: /* Tower */
2180 	case 0x10: /* Lunch Box */
2181 	case 0x11: /* Main Server Chassis */
2182 		return true;
2183 	}
2184 
2185 	return false;
2186 }
2187 
2188 /*
2189  * We're seeing a lot of bogus backlight interfaces on newer machines
2190  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2191  * lcd flag fixes this, enable this by default on any machines which are:
2192  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2193  *     normally the acpi_video code should not register there anyways); *and*
2194  * 2.1 Report a desktop/server DMI chassis-type, or
2195  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2196        backlight control)
2197  */
2198 static bool should_check_lcd_flag(void)
2199 {
2200 	if (!acpi_osi_is_win8())
2201 		return false;
2202 
2203 	if (dmi_is_desktop())
2204 		return true;
2205 
2206 	if (acpi_reduced_hardware())
2207 		return true;
2208 
2209 	return false;
2210 }
2211 
2212 int acpi_video_register(void)
2213 {
2214 	int ret = 0;
2215 
2216 	mutex_lock(&register_count_mutex);
2217 	if (register_count) {
2218 		/*
2219 		 * if the function of acpi_video_register is already called,
2220 		 * don't register the acpi_video_bus again and return no error.
2221 		 */
2222 		goto leave;
2223 	}
2224 
2225 	if (only_lcd == -1)
2226 		only_lcd = should_check_lcd_flag();
2227 
2228 	dmi_check_system(video_dmi_table);
2229 
2230 	ret = acpi_bus_register_driver(&acpi_video_bus);
2231 	if (ret)
2232 		goto leave;
2233 
2234 	/*
2235 	 * When the acpi_video_bus is loaded successfully, increase
2236 	 * the counter reference.
2237 	 */
2238 	register_count = 1;
2239 
2240 leave:
2241 	mutex_unlock(&register_count_mutex);
2242 	return ret;
2243 }
2244 EXPORT_SYMBOL(acpi_video_register);
2245 
2246 void acpi_video_unregister(void)
2247 {
2248 	mutex_lock(&register_count_mutex);
2249 	if (register_count) {
2250 		acpi_bus_unregister_driver(&acpi_video_bus);
2251 		register_count = 0;
2252 	}
2253 	mutex_unlock(&register_count_mutex);
2254 }
2255 EXPORT_SYMBOL(acpi_video_unregister);
2256 
2257 void acpi_video_unregister_backlight(void)
2258 {
2259 	struct acpi_video_bus *video;
2260 
2261 	mutex_lock(&register_count_mutex);
2262 	if (register_count) {
2263 		mutex_lock(&video_list_lock);
2264 		list_for_each_entry(video, &video_bus_head, entry)
2265 			acpi_video_bus_unregister_backlight(video);
2266 		mutex_unlock(&video_list_lock);
2267 	}
2268 	mutex_unlock(&register_count_mutex);
2269 }
2270 
2271 bool acpi_video_handles_brightness_key_presses(void)
2272 {
2273 	bool have_video_busses;
2274 
2275 	mutex_lock(&video_list_lock);
2276 	have_video_busses = !list_empty(&video_bus_head);
2277 	mutex_unlock(&video_list_lock);
2278 
2279 	return have_video_busses &&
2280 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2281 }
2282 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2283 
2284 /*
2285  * This is kind of nasty. Hardware using Intel chipsets may require
2286  * the video opregion code to be run first in order to initialise
2287  * state before any ACPI video calls are made. To handle this we defer
2288  * registration of the video class until the opregion code has run.
2289  */
2290 
2291 static int __init acpi_video_init(void)
2292 {
2293 	/*
2294 	 * Let the module load even if ACPI is disabled (e.g. due to
2295 	 * a broken BIOS) so that i915.ko can still be loaded on such
2296 	 * old systems without an AcpiOpRegion.
2297 	 *
2298 	 * acpi_video_register() will report -ENODEV later as well due
2299 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2300 	 */
2301 	if (acpi_disabled)
2302 		return 0;
2303 
2304 	if (intel_opregion_present())
2305 		return 0;
2306 
2307 	return acpi_video_register();
2308 }
2309 
2310 static void __exit acpi_video_exit(void)
2311 {
2312 	acpi_video_detect_exit();
2313 	acpi_video_unregister();
2314 }
2315 
2316 module_init(acpi_video_init);
2317 module_exit(acpi_video_exit);
2318