xref: /linux/drivers/acpi/acpi_video.c (revision a634dda26186cf9a51567020fcce52bcba5e1e59)
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 #define REPORT_OUTPUT_KEY_EVENTS		0x01
51 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
52 static int report_key_events = -1;
53 module_param(report_key_events, int, 0644);
54 MODULE_PARM_DESC(report_key_events,
55 	"0: none, 1: output changes, 2: brightness changes, 3: all");
56 
57 static int hw_changes_brightness = -1;
58 module_param(hw_changes_brightness, int, 0644);
59 MODULE_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  */
67 static bool device_id_scheme = false;
68 module_param(device_id_scheme, bool, 0444);
69 
70 static int only_lcd;
71 module_param(only_lcd, int, 0444);
72 
73 static bool may_report_brightness_keys;
74 static int register_count;
75 static DEFINE_MUTEX(register_count_mutex);
76 static DEFINE_MUTEX(video_list_lock);
77 static LIST_HEAD(video_bus_head);
78 static int acpi_video_bus_add(struct acpi_device *device);
79 static void acpi_video_bus_remove(struct acpi_device *device);
80 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data);
81 
82 /*
83  * Indices in the _BCL method response: the first two items are special,
84  * the rest are all supported levels.
85  *
86  * See page 575 of the ACPI spec 3.0
87  */
88 enum acpi_video_level_idx {
89 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
90 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
91 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
92 };
93 
94 static const struct acpi_device_id video_device_ids[] = {
95 	{ACPI_VIDEO_HID, 0},
96 	{"", 0},
97 };
98 MODULE_DEVICE_TABLE(acpi, video_device_ids);
99 
100 static struct acpi_driver acpi_video_bus = {
101 	.name = "video",
102 	.class = ACPI_VIDEO_CLASS,
103 	.ids = video_device_ids,
104 	.ops = {
105 		.add = acpi_video_bus_add,
106 		.remove = acpi_video_bus_remove,
107 		},
108 };
109 
110 struct acpi_video_bus_flags {
111 	u8 multihead:1;		/* can switch video heads */
112 	u8 rom:1;		/* can retrieve a video rom */
113 	u8 post:1;		/* can configure the head to */
114 	u8 reserved:5;
115 };
116 
117 struct acpi_video_bus_cap {
118 	u8 _DOS:1;		/* Enable/Disable output switching */
119 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
120 	u8 _ROM:1;		/* Get ROM Data */
121 	u8 _GPD:1;		/* Get POST Device */
122 	u8 _SPD:1;		/* Set POST Device */
123 	u8 _VPO:1;		/* Video POST Options */
124 	u8 reserved:2;
125 };
126 
127 struct acpi_video_device_attrib {
128 	u32 display_index:4;	/* A zero-based instance of the Display */
129 	u32 display_port_attachment:4;	/* This field differentiates the display type */
130 	u32 display_type:4;	/* Describe the specific type in use */
131 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
132 	u32 bios_can_detect:1;	/* BIOS can detect the device */
133 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
134 				   the VGA device. */
135 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
136 	u32 reserved:10;	/* Must be 0 */
137 
138 	/*
139 	 * The device ID might not actually follow the scheme described by this
140 	 * struct acpi_video_device_attrib. If it does, then this bit
141 	 * device_id_scheme is set; otherwise, other fields should be ignored.
142 	 *
143 	 * (but also see the global flag device_id_scheme)
144 	 */
145 	u32 device_id_scheme:1;
146 };
147 
148 struct acpi_video_enumerated_device {
149 	union {
150 		u32 int_val;
151 		struct acpi_video_device_attrib attrib;
152 	} value;
153 	struct acpi_video_device *bind_info;
154 };
155 
156 struct acpi_video_bus {
157 	struct acpi_device *device;
158 	bool backlight_registered;
159 	u8 dos_setting;
160 	struct acpi_video_enumerated_device *attached_array;
161 	u8 attached_count;
162 	u8 child_count;
163 	struct acpi_video_bus_cap cap;
164 	struct acpi_video_bus_flags flags;
165 	struct list_head video_device_list;
166 	struct mutex device_list_lock;	/* protects video_device_list */
167 	struct list_head entry;
168 	struct input_dev *input;
169 	char phys[32];	/* for input device */
170 	struct notifier_block pm_nb;
171 };
172 
173 struct acpi_video_device_flags {
174 	u8 crt:1;
175 	u8 lcd:1;
176 	u8 tvout:1;
177 	u8 dvi:1;
178 	u8 bios:1;
179 	u8 unknown:1;
180 	u8 notify:1;
181 	u8 reserved:1;
182 };
183 
184 struct acpi_video_device_cap {
185 	u8 _ADR:1;		/* Return the unique ID */
186 	u8 _BCL:1;		/* Query list of brightness control levels supported */
187 	u8 _BCM:1;		/* Set the brightness level */
188 	u8 _BQC:1;		/* Get current brightness level */
189 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
190 	u8 _DDC:1;		/* Return the EDID for this device */
191 };
192 
193 struct acpi_video_device {
194 	unsigned long device_id;
195 	struct acpi_video_device_flags flags;
196 	struct acpi_video_device_cap cap;
197 	struct list_head entry;
198 	struct delayed_work switch_brightness_work;
199 	int switch_brightness_event;
200 	struct acpi_video_bus *video;
201 	struct acpi_device *dev;
202 	struct acpi_video_device_brightness *brightness;
203 	struct backlight_device *backlight;
204 	struct thermal_cooling_device *cooling_dev;
205 };
206 
207 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
208 static void acpi_video_device_rebind(struct acpi_video_bus *video);
209 static void acpi_video_device_bind(struct acpi_video_bus *video,
210 				   struct acpi_video_device *device);
211 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
212 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
213 			int level);
214 static int acpi_video_device_lcd_get_level_current(
215 			struct acpi_video_device *device,
216 			unsigned long long *level, bool raw);
217 static int acpi_video_get_next_level(struct acpi_video_device *device,
218 				     u32 level_current, u32 event);
219 static void acpi_video_switch_brightness(struct work_struct *work);
220 
221 /* backlight device sysfs support */
222 static int acpi_video_get_brightness(struct backlight_device *bd)
223 {
224 	unsigned long long cur_level;
225 	int i;
226 	struct acpi_video_device *vd = bl_get_data(bd);
227 
228 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
229 		return -EINVAL;
230 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
231 		if (vd->brightness->levels[i] == cur_level)
232 			return i - ACPI_VIDEO_FIRST_LEVEL;
233 	}
234 	return 0;
235 }
236 
237 static int acpi_video_set_brightness(struct backlight_device *bd)
238 {
239 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
240 	struct acpi_video_device *vd = bl_get_data(bd);
241 
242 	cancel_delayed_work(&vd->switch_brightness_work);
243 	return acpi_video_device_lcd_set_level(vd,
244 				vd->brightness->levels[request_level]);
245 }
246 
247 static const struct backlight_ops acpi_backlight_ops = {
248 	.get_brightness = acpi_video_get_brightness,
249 	.update_status  = acpi_video_set_brightness,
250 };
251 
252 /* thermal cooling device callbacks */
253 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
254 			       unsigned long *state)
255 {
256 	struct acpi_video_device *video = cooling_dev->devdata;
257 
258 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
259 	return 0;
260 }
261 
262 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
263 			       unsigned long *state)
264 {
265 	struct acpi_video_device *video = cooling_dev->devdata;
266 	unsigned long long level;
267 	int offset;
268 
269 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
270 		return -EINVAL;
271 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
272 	     offset++)
273 		if (level == video->brightness->levels[offset]) {
274 			*state = video->brightness->count - offset - 1;
275 			return 0;
276 		}
277 
278 	return -EINVAL;
279 }
280 
281 static int
282 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
283 {
284 	struct acpi_video_device *video = cooling_dev->devdata;
285 	int level;
286 
287 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
288 		return -EINVAL;
289 
290 	state = video->brightness->count - state;
291 	level = video->brightness->levels[state - 1];
292 	return acpi_video_device_lcd_set_level(video, level);
293 }
294 
295 static const struct thermal_cooling_device_ops video_cooling_ops = {
296 	.get_max_state = video_get_max_state,
297 	.get_cur_state = video_get_cur_state,
298 	.set_cur_state = video_set_cur_state,
299 };
300 
301 /*
302  * --------------------------------------------------------------------------
303  *                             Video Management
304  * --------------------------------------------------------------------------
305  */
306 
307 static int
308 acpi_video_device_lcd_query_levels(acpi_handle handle,
309 				   union acpi_object **levels)
310 {
311 	int status;
312 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
313 	union acpi_object *obj;
314 
315 
316 	*levels = NULL;
317 
318 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
319 	if (ACPI_FAILURE(status))
320 		return status;
321 	obj = (union acpi_object *)buffer.pointer;
322 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
323 		acpi_handle_info(handle, "Invalid _BCL data\n");
324 		status = -EFAULT;
325 		goto err;
326 	}
327 
328 	*levels = obj;
329 
330 	return 0;
331 
332 err:
333 	kfree(buffer.pointer);
334 
335 	return status;
336 }
337 
338 static int
339 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
340 {
341 	int status;
342 	int state;
343 
344 	status = acpi_execute_simple_method(device->dev->handle,
345 					    "_BCM", level);
346 	if (ACPI_FAILURE(status)) {
347 		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
348 		return -EIO;
349 	}
350 
351 	device->brightness->curr = level;
352 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
353 	     state++)
354 		if (level == device->brightness->levels[state]) {
355 			if (device->backlight)
356 				device->backlight->props.brightness =
357 					state - ACPI_VIDEO_FIRST_LEVEL;
358 			return 0;
359 		}
360 
361 	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
362 	return -EINVAL;
363 }
364 
365 /*
366  * For some buggy _BQC methods, we need to add a constant value to
367  * the _BQC return value to get the actual current brightness level
368  */
369 
370 static int bqc_offset_aml_bug_workaround;
371 static int video_set_bqc_offset(const struct dmi_system_id *d)
372 {
373 	bqc_offset_aml_bug_workaround = 9;
374 	return 0;
375 }
376 
377 static int video_set_device_id_scheme(const struct dmi_system_id *d)
378 {
379 	device_id_scheme = true;
380 	return 0;
381 }
382 
383 static int video_enable_only_lcd(const struct dmi_system_id *d)
384 {
385 	only_lcd = true;
386 	return 0;
387 }
388 
389 static int video_set_report_key_events(const struct dmi_system_id *id)
390 {
391 	if (report_key_events == -1)
392 		report_key_events = (uintptr_t)id->driver_data;
393 	return 0;
394 }
395 
396 static int video_hw_changes_brightness(
397 	const struct dmi_system_id *d)
398 {
399 	if (hw_changes_brightness == -1)
400 		hw_changes_brightness = 1;
401 	return 0;
402 }
403 
404 static const struct dmi_system_id video_dmi_table[] = {
405 	/*
406 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
407 	 */
408 	{
409 	 .callback = video_set_bqc_offset,
410 	 .ident = "Acer Aspire 5720",
411 	 .matches = {
412 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
413 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
414 		},
415 	},
416 	{
417 	 .callback = video_set_bqc_offset,
418 	 .ident = "Acer Aspire 5710Z",
419 	 .matches = {
420 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
421 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
422 		},
423 	},
424 	{
425 	 .callback = video_set_bqc_offset,
426 	 .ident = "eMachines E510",
427 	 .matches = {
428 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
429 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
430 		},
431 	},
432 	{
433 	 .callback = video_set_bqc_offset,
434 	 .ident = "Acer Aspire 5315",
435 	 .matches = {
436 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
437 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
438 		},
439 	},
440 	{
441 	 .callback = video_set_bqc_offset,
442 	 .ident = "Acer Aspire 7720",
443 	 .matches = {
444 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
445 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
446 		},
447 	},
448 
449 	/*
450 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
451 	 * but the IDs actually follow the Device ID Scheme.
452 	 */
453 	{
454 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
455 	 .callback = video_set_device_id_scheme,
456 	 .ident = "ESPRIMO Mobile M9410",
457 	 .matches = {
458 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
459 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
460 		},
461 	},
462 	/*
463 	 * Some machines have multiple video output devices, but only the one
464 	 * that is the type of LCD can do the backlight control so we should not
465 	 * register backlight interface for other video output devices.
466 	 */
467 	{
468 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
469 	 .callback = video_enable_only_lcd,
470 	 .ident = "ESPRIMO Mobile M9410",
471 	 .matches = {
472 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
473 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
474 		},
475 	},
476 	/*
477 	 * Some machines report wrong key events on the acpi-bus, suppress
478 	 * key event reporting on these.  Note this is only intended to work
479 	 * around events which are plain wrong. In some cases we get double
480 	 * events, in this case acpi-video is considered the canonical source
481 	 * and the events from the other source should be filtered. E.g.
482 	 * by calling acpi_video_handles_brightness_key_presses() from the
483 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
484 	 */
485 	{
486 	 .callback = video_set_report_key_events,
487 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
488 	 .ident = "Dell Vostro V131",
489 	 .matches = {
490 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
491 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
492 		},
493 	},
494 	{
495 	 .callback = video_set_report_key_events,
496 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
497 	 .ident = "Dell Vostro 3350",
498 	 .matches = {
499 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
500 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
501 		},
502 	},
503 	{
504 	 .callback = video_set_report_key_events,
505 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
506 	 .ident = "COLORFUL X15 AT 23",
507 	 .matches = {
508 		DMI_MATCH(DMI_SYS_VENDOR, "COLORFUL"),
509 		DMI_MATCH(DMI_PRODUCT_NAME, "X15 AT 23"),
510 		},
511 	},
512 	/*
513 	 * Some machines change the brightness themselves when a brightness
514 	 * hotkey gets pressed, despite us telling them not to. In this case
515 	 * acpi_video_device_notify() should only call backlight_force_update(
516 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
517 	 */
518 	{
519 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
520 	 .callback = video_hw_changes_brightness,
521 	 .ident = "Packard Bell EasyNote MZ35",
522 	 .matches = {
523 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
524 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
525 		},
526 	},
527 	{}
528 };
529 
530 static unsigned long long
531 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
532 			      unsigned long long bqc_value)
533 {
534 	unsigned long long level;
535 
536 	if (device->brightness->flags._BQC_use_index) {
537 		/*
538 		 * _BQC returns an index that doesn't account for the first 2
539 		 * items with special meaning (see enum acpi_video_level_idx),
540 		 * so we need to compensate for that by offsetting ourselves
541 		 */
542 		if (device->brightness->flags._BCL_reversed)
543 			bqc_value = device->brightness->count -
544 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
545 
546 		level = device->brightness->levels[bqc_value +
547 						   ACPI_VIDEO_FIRST_LEVEL];
548 	} else {
549 		level = bqc_value;
550 	}
551 
552 	level += bqc_offset_aml_bug_workaround;
553 
554 	return level;
555 }
556 
557 static int
558 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
559 					unsigned long long *level, bool raw)
560 {
561 	acpi_status status = AE_OK;
562 	int i;
563 
564 	if (device->cap._BQC || device->cap._BCQ) {
565 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
566 
567 		status = acpi_evaluate_integer(device->dev->handle, buf,
568 						NULL, level);
569 		if (ACPI_SUCCESS(status)) {
570 			if (raw) {
571 				/*
572 				 * Caller has indicated he wants the raw
573 				 * value returned by _BQC, so don't furtherly
574 				 * mess with the value.
575 				 */
576 				return 0;
577 			}
578 
579 			*level = acpi_video_bqc_value_to_level(device, *level);
580 
581 			for (i = ACPI_VIDEO_FIRST_LEVEL;
582 			     i < device->brightness->count; i++)
583 				if (device->brightness->levels[i] == *level) {
584 					device->brightness->curr = *level;
585 					return 0;
586 				}
587 			/*
588 			 * BQC returned an invalid level.
589 			 * Stop using it.
590 			 */
591 			acpi_handle_info(device->dev->handle,
592 					 "%s returned an invalid level", buf);
593 			device->cap._BQC = device->cap._BCQ = 0;
594 		} else {
595 			/*
596 			 * Fixme:
597 			 * should we return an error or ignore this failure?
598 			 * dev->brightness->curr is a cached value which stores
599 			 * the correct current backlight level in most cases.
600 			 * ACPI video backlight still works w/ buggy _BQC.
601 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
602 			 */
603 			acpi_handle_info(device->dev->handle,
604 					 "%s evaluation failed", buf);
605 			device->cap._BQC = device->cap._BCQ = 0;
606 		}
607 	}
608 
609 	*level = device->brightness->curr;
610 	return 0;
611 }
612 
613 /**
614  * acpi_video_device_EDID() - Get EDID from ACPI _DDC
615  * @device: video output device (LCD, CRT, ..)
616  * @edid: address for returned EDID pointer
617  * @length: _DDC length to request (must be a multiple of 128)
618  *
619  * Get EDID from ACPI _DDC. On success, a pointer to the EDID data is written
620  * to the @edid address, and the length of the EDID is returned. The caller is
621  * responsible for freeing the edid pointer.
622  *
623  * Return the length of EDID (positive value) on success or error (negative
624  * value).
625  */
626 static int
627 acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length)
628 {
629 	acpi_status status;
630 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
631 	union acpi_object *obj;
632 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
633 	struct acpi_object_list args = { 1, &arg0 };
634 	int ret;
635 
636 	*edid = NULL;
637 
638 	if (!device)
639 		return -ENODEV;
640 	if (!length || (length % 128))
641 		return -EINVAL;
642 
643 	arg0.integer.value = length / 128;
644 
645 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
646 	if (ACPI_FAILURE(status))
647 		return -ENODEV;
648 
649 	obj = buffer.pointer;
650 
651 	if (obj && obj->type == ACPI_TYPE_BUFFER) {
652 		*edid = kmemdup(obj->buffer.pointer, obj->buffer.length, GFP_KERNEL);
653 		ret = *edid ? obj->buffer.length : -ENOMEM;
654 	} else {
655 		acpi_handle_debug(device->dev->handle,
656 				 "Invalid _DDC data for length %d\n", length);
657 		ret = -EFAULT;
658 	}
659 
660 	kfree(obj);
661 	return ret;
662 }
663 
664 /* bus */
665 
666 /*
667  *  Arg:
668  *	video		: video bus device pointer
669  *	bios_flag	:
670  *		0.	The system BIOS should NOT automatically switch(toggle)
671  *			the active display output.
672  *		1.	The system BIOS should automatically switch (toggle) the
673  *			active display output. No switch event.
674  *		2.	The _DGS value should be locked.
675  *		3.	The system BIOS should not automatically switch (toggle) the
676  *			active display output, but instead generate the display switch
677  *			event notify code.
678  *	lcd_flag	:
679  *		0.	The system BIOS should automatically control the brightness level
680  *			of the LCD when:
681  *			- the power changes from AC to DC (ACPI appendix B)
682  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
683  *		1.	The system BIOS should NOT automatically control the brightness
684  *			level of the LCD when:
685  *			- the power changes from AC to DC (ACPI appendix B)
686  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
687  *  Return Value:
688  *		-EINVAL	wrong arg.
689  */
690 
691 static int
692 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
693 {
694 	acpi_status status;
695 
696 	if (!video->cap._DOS)
697 		return 0;
698 
699 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
700 		return -EINVAL;
701 	video->dos_setting = (lcd_flag << 2) | bios_flag;
702 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
703 					    (lcd_flag << 2) | bios_flag);
704 	if (ACPI_FAILURE(status))
705 		return -EIO;
706 
707 	return 0;
708 }
709 
710 /*
711  * Simple comparison function used to sort backlight levels.
712  */
713 
714 static int
715 acpi_video_cmp_level(const void *a, const void *b)
716 {
717 	return *(int *)a - *(int *)b;
718 }
719 
720 /*
721  * Decides if _BQC/_BCQ for this system is usable
722  *
723  * We do this by changing the level first and then read out the current
724  * brightness level, if the value does not match, find out if it is using
725  * index. If not, clear the _BQC/_BCQ capability.
726  */
727 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
728 				int max_level, int current_level)
729 {
730 	struct acpi_video_device_brightness *br = device->brightness;
731 	int result;
732 	unsigned long long level;
733 	int test_level;
734 
735 	/* don't mess with existing known broken systems */
736 	if (bqc_offset_aml_bug_workaround)
737 		return 0;
738 
739 	/*
740 	 * Some systems always report current brightness level as maximum
741 	 * through _BQC, we need to test another value for them. However,
742 	 * there is a subtlety:
743 	 *
744 	 * If the _BCL package ordering is descending, the first level
745 	 * (br->levels[2]) is likely to be 0, and if the number of levels
746 	 * matches the number of steps, we might confuse a returned level to
747 	 * mean the index.
748 	 *
749 	 * For example:
750 	 *
751 	 *     current_level = max_level = 100
752 	 *     test_level = 0
753 	 *     returned level = 100
754 	 *
755 	 * In this case 100 means the level, not the index, and _BCM failed.
756 	 * Still, if the _BCL package ordering is descending, the index of
757 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
758 	 *
759 	 * This causes all _BQC calls to return bogus values causing weird
760 	 * behavior from the user's perspective.  For example:
761 	 *
762 	 * xbacklight -set 10; xbacklight -set 20;
763 	 *
764 	 * would flash to 90% and then slowly down to the desired level (20).
765 	 *
766 	 * The solution is simple; test anything other than the first level
767 	 * (e.g. 1).
768 	 */
769 	test_level = current_level == max_level
770 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
771 		: max_level;
772 
773 	result = acpi_video_device_lcd_set_level(device, test_level);
774 	if (result)
775 		return result;
776 
777 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
778 	if (result)
779 		return result;
780 
781 	if (level != test_level) {
782 		/* buggy _BQC found, need to find out if it uses index */
783 		if (level < br->count) {
784 			if (br->flags._BCL_reversed)
785 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
786 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
787 				br->flags._BQC_use_index = 1;
788 		}
789 
790 		if (!br->flags._BQC_use_index)
791 			device->cap._BQC = device->cap._BCQ = 0;
792 	}
793 
794 	return 0;
795 }
796 
797 int acpi_video_get_levels(struct acpi_device *device,
798 			  struct acpi_video_device_brightness **dev_br,
799 			  int *pmax_level)
800 {
801 	union acpi_object *obj = NULL;
802 	int i, max_level = 0, count = 0, level_ac_battery = 0;
803 	union acpi_object *o;
804 	struct acpi_video_device_brightness *br = NULL;
805 	int result = 0;
806 	u32 value;
807 
808 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
809 		acpi_handle_debug(device->handle,
810 				  "Could not query available LCD brightness level\n");
811 		result = -ENODEV;
812 		goto out;
813 	}
814 
815 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
816 		result = -EINVAL;
817 		goto out;
818 	}
819 
820 	br = kzalloc(sizeof(*br), GFP_KERNEL);
821 	if (!br) {
822 		result = -ENOMEM;
823 		goto out;
824 	}
825 
826 	/*
827 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
828 	 * in order to account for buggy BIOS which don't export the first two
829 	 * special levels (see below)
830 	 */
831 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
832 				   sizeof(*br->levels),
833 				   GFP_KERNEL);
834 	if (!br->levels) {
835 		result = -ENOMEM;
836 		goto out_free;
837 	}
838 
839 	for (i = 0; i < obj->package.count; i++) {
840 		o = (union acpi_object *)&obj->package.elements[i];
841 		if (o->type != ACPI_TYPE_INTEGER) {
842 			acpi_handle_info(device->handle, "Invalid data\n");
843 			continue;
844 		}
845 		value = (u32) o->integer.value;
846 		/* Skip duplicate entries */
847 		if (count > ACPI_VIDEO_FIRST_LEVEL
848 		    && br->levels[count - 1] == value)
849 			continue;
850 
851 		br->levels[count] = value;
852 
853 		if (br->levels[count] > max_level)
854 			max_level = br->levels[count];
855 		count++;
856 	}
857 
858 	/*
859 	 * some buggy BIOS don't export the levels
860 	 * when machine is on AC/Battery in _BCL package.
861 	 * In this case, the first two elements in _BCL packages
862 	 * are also supported brightness levels that OS should take care of.
863 	 */
864 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
865 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
866 			level_ac_battery++;
867 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
868 			level_ac_battery++;
869 	}
870 
871 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
872 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
873 		br->flags._BCL_no_ac_battery_levels = 1;
874 		for (i = (count - 1 + level_ac_battery);
875 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
876 			br->levels[i] = br->levels[i - level_ac_battery];
877 		count += level_ac_battery;
878 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
879 		acpi_handle_info(device->handle,
880 				 "Too many duplicates in _BCL package");
881 
882 	/* Check if the _BCL package is in a reversed order */
883 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
884 		br->flags._BCL_reversed = 1;
885 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
886 		     count - ACPI_VIDEO_FIRST_LEVEL,
887 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
888 		     acpi_video_cmp_level, NULL);
889 	} else if (max_level != br->levels[count - 1])
890 		acpi_handle_info(device->handle,
891 				 "Found unordered _BCL package");
892 
893 	br->count = count;
894 	*dev_br = br;
895 	if (pmax_level)
896 		*pmax_level = max_level;
897 
898 out:
899 	kfree(obj);
900 	return result;
901 out_free:
902 	kfree(br);
903 	goto out;
904 }
905 EXPORT_SYMBOL(acpi_video_get_levels);
906 
907 /*
908  *  Arg:
909  *	device	: video output device (LCD, CRT, ..)
910  *
911  *  Return Value:
912  *	Maximum brightness level
913  *
914  *  Allocate and initialize device->brightness.
915  */
916 
917 static int
918 acpi_video_init_brightness(struct acpi_video_device *device)
919 {
920 	int i, max_level = 0;
921 	unsigned long long level, level_old;
922 	struct acpi_video_device_brightness *br = NULL;
923 	int result;
924 
925 	result = acpi_video_get_levels(device->dev, &br, &max_level);
926 	if (result)
927 		return result;
928 	device->brightness = br;
929 
930 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
931 	br->curr = level = max_level;
932 
933 	if (!device->cap._BQC)
934 		goto set_level;
935 
936 	result = acpi_video_device_lcd_get_level_current(device,
937 							 &level_old, true);
938 	if (result)
939 		goto out_free_levels;
940 
941 	result = acpi_video_bqc_quirk(device, max_level, level_old);
942 	if (result)
943 		goto out_free_levels;
944 	/*
945 	 * cap._BQC may get cleared due to _BQC is found to be broken
946 	 * in acpi_video_bqc_quirk, so check again here.
947 	 */
948 	if (!device->cap._BQC)
949 		goto set_level;
950 
951 	level = acpi_video_bqc_value_to_level(device, level_old);
952 	/*
953 	 * On some buggy laptops, _BQC returns an uninitialized
954 	 * value when invoked for the first time, i.e.
955 	 * level_old is invalid (no matter whether it's a level
956 	 * or an index). Set the backlight to max_level in this case.
957 	 */
958 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
959 		if (level == br->levels[i])
960 			break;
961 	if (i == br->count || !level)
962 		level = max_level;
963 
964 set_level:
965 	result = acpi_video_device_lcd_set_level(device, level);
966 	if (result)
967 		goto out_free_levels;
968 
969 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
970 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
971 
972 	return 0;
973 
974 out_free_levels:
975 	kfree(br->levels);
976 	kfree(br);
977 	device->brightness = NULL;
978 	return result;
979 }
980 
981 /*
982  *  Arg:
983  *	device	: video output device (LCD, CRT, ..)
984  *
985  *  Return Value:
986  *	None
987  *
988  *  Find out all required AML methods defined under the output
989  *  device.
990  */
991 
992 static void acpi_video_device_find_cap(struct acpi_video_device *device)
993 {
994 	if (acpi_has_method(device->dev->handle, "_ADR"))
995 		device->cap._ADR = 1;
996 	if (acpi_has_method(device->dev->handle, "_BCL"))
997 		device->cap._BCL = 1;
998 	if (acpi_has_method(device->dev->handle, "_BCM"))
999 		device->cap._BCM = 1;
1000 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1001 		device->cap._BQC = 1;
1002 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1003 		acpi_handle_info(device->dev->handle,
1004 				 "_BCQ is used instead of _BQC\n");
1005 		device->cap._BCQ = 1;
1006 	}
1007 
1008 	if (acpi_has_method(device->dev->handle, "_DDC"))
1009 		device->cap._DDC = 1;
1010 }
1011 
1012 /*
1013  *  Arg:
1014  *	device	: video output device (VGA)
1015  *
1016  *  Return Value:
1017  *	None
1018  *
1019  *  Find out all required AML methods defined under the video bus device.
1020  */
1021 
1022 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1023 {
1024 	if (acpi_has_method(video->device->handle, "_DOS"))
1025 		video->cap._DOS = 1;
1026 	if (acpi_has_method(video->device->handle, "_DOD"))
1027 		video->cap._DOD = 1;
1028 	if (acpi_has_method(video->device->handle, "_ROM"))
1029 		video->cap._ROM = 1;
1030 	if (acpi_has_method(video->device->handle, "_GPD"))
1031 		video->cap._GPD = 1;
1032 	if (acpi_has_method(video->device->handle, "_SPD"))
1033 		video->cap._SPD = 1;
1034 	if (acpi_has_method(video->device->handle, "_VPO"))
1035 		video->cap._VPO = 1;
1036 }
1037 
1038 /*
1039  * Check whether the video bus device has required AML method to
1040  * support the desired features
1041  */
1042 
1043 static int acpi_video_bus_check(struct acpi_video_bus *video)
1044 {
1045 	acpi_status status = -ENOENT;
1046 	struct pci_dev *dev;
1047 
1048 	if (!video)
1049 		return -EINVAL;
1050 
1051 	dev = acpi_get_pci_dev(video->device->handle);
1052 	if (!dev)
1053 		return -ENODEV;
1054 	pci_dev_put(dev);
1055 
1056 	/*
1057 	 * Since there is no HID, CID and so on for VGA driver, we have
1058 	 * to check well known required nodes.
1059 	 */
1060 
1061 	/* Does this device support video switching? */
1062 	if (video->cap._DOS || video->cap._DOD) {
1063 		if (!video->cap._DOS) {
1064 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1065 				acpi_device_bid(video->device));
1066 		}
1067 		video->flags.multihead = 1;
1068 		status = 0;
1069 	}
1070 
1071 	/* Does this device support retrieving a video ROM? */
1072 	if (video->cap._ROM) {
1073 		video->flags.rom = 1;
1074 		status = 0;
1075 	}
1076 
1077 	/* Does this device support configuring which video device to POST? */
1078 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1079 		video->flags.post = 1;
1080 		status = 0;
1081 	}
1082 
1083 	return status;
1084 }
1085 
1086 /*
1087  * --------------------------------------------------------------------------
1088  *                               Driver Interface
1089  * --------------------------------------------------------------------------
1090  */
1091 
1092 /* device interface */
1093 static struct acpi_video_device_attrib *
1094 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1095 {
1096 	struct acpi_video_enumerated_device *ids;
1097 	int i;
1098 
1099 	for (i = 0; i < video->attached_count; i++) {
1100 		ids = &video->attached_array[i];
1101 		if ((ids->value.int_val & 0xffff) == device_id)
1102 			return &ids->value.attrib;
1103 	}
1104 
1105 	return NULL;
1106 }
1107 
1108 static int
1109 acpi_video_get_device_type(struct acpi_video_bus *video,
1110 			   unsigned long device_id)
1111 {
1112 	struct acpi_video_enumerated_device *ids;
1113 	int i;
1114 
1115 	for (i = 0; i < video->attached_count; i++) {
1116 		ids = &video->attached_array[i];
1117 		if ((ids->value.int_val & 0xffff) == device_id)
1118 			return ids->value.int_val;
1119 	}
1120 
1121 	return 0;
1122 }
1123 
1124 static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
1125 {
1126 	struct acpi_video_bus *video = arg;
1127 	struct acpi_video_device_attrib *attribute;
1128 	struct acpi_video_device *data;
1129 	unsigned long long device_id;
1130 	acpi_status status;
1131 	int device_type;
1132 
1133 	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1134 	/* Skip devices without _ADR instead of failing. */
1135 	if (ACPI_FAILURE(status))
1136 		goto exit;
1137 
1138 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1139 	if (!data) {
1140 		dev_dbg(&device->dev, "Cannot attach\n");
1141 		return -ENOMEM;
1142 	}
1143 
1144 	strscpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1145 	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1146 
1147 	data->device_id = device_id;
1148 	data->video = video;
1149 	data->dev = device;
1150 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1151 			  acpi_video_switch_brightness);
1152 
1153 	attribute = acpi_video_get_device_attr(video, device_id);
1154 
1155 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1156 		switch (attribute->display_type) {
1157 		case ACPI_VIDEO_DISPLAY_CRT:
1158 			data->flags.crt = 1;
1159 			break;
1160 		case ACPI_VIDEO_DISPLAY_TV:
1161 			data->flags.tvout = 1;
1162 			break;
1163 		case ACPI_VIDEO_DISPLAY_DVI:
1164 			data->flags.dvi = 1;
1165 			break;
1166 		case ACPI_VIDEO_DISPLAY_LCD:
1167 			data->flags.lcd = 1;
1168 			break;
1169 		default:
1170 			data->flags.unknown = 1;
1171 			break;
1172 		}
1173 		if (attribute->bios_can_detect)
1174 			data->flags.bios = 1;
1175 	} else {
1176 		/* Check for legacy IDs */
1177 		device_type = acpi_video_get_device_type(video, device_id);
1178 		/* Ignore bits 16 and 18-20 */
1179 		switch (device_type & 0xffe2ffff) {
1180 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1181 			data->flags.crt = 1;
1182 			break;
1183 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1184 			data->flags.lcd = 1;
1185 			break;
1186 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1187 			data->flags.tvout = 1;
1188 			break;
1189 		default:
1190 			data->flags.unknown = 1;
1191 		}
1192 	}
1193 
1194 	acpi_video_device_bind(video, data);
1195 	acpi_video_device_find_cap(data);
1196 
1197 	if (data->cap._BCM && data->cap._BCL)
1198 		may_report_brightness_keys = true;
1199 
1200 	mutex_lock(&video->device_list_lock);
1201 	list_add_tail(&data->entry, &video->video_device_list);
1202 	mutex_unlock(&video->device_list_lock);
1203 
1204 exit:
1205 	video->child_count++;
1206 	return 0;
1207 }
1208 
1209 /*
1210  *  Arg:
1211  *	video	: video bus device
1212  *
1213  *  Return:
1214  *	none
1215  *
1216  *  Enumerate the video device list of the video bus,
1217  *  bind the ids with the corresponding video devices
1218  *  under the video bus.
1219  */
1220 
1221 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1222 {
1223 	struct acpi_video_device *dev;
1224 
1225 	mutex_lock(&video->device_list_lock);
1226 
1227 	list_for_each_entry(dev, &video->video_device_list, entry)
1228 		acpi_video_device_bind(video, dev);
1229 
1230 	mutex_unlock(&video->device_list_lock);
1231 }
1232 
1233 /*
1234  *  Arg:
1235  *	video	: video bus device
1236  *	device	: video output device under the video
1237  *		bus
1238  *
1239  *  Return:
1240  *	none
1241  *
1242  *  Bind the ids with the corresponding video devices
1243  *  under the video bus.
1244  */
1245 
1246 static void
1247 acpi_video_device_bind(struct acpi_video_bus *video,
1248 		       struct acpi_video_device *device)
1249 {
1250 	struct acpi_video_enumerated_device *ids;
1251 	int i;
1252 
1253 	for (i = 0; i < video->attached_count; i++) {
1254 		ids = &video->attached_array[i];
1255 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1256 			ids->bind_info = device;
1257 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1258 					  __func__, i);
1259 		}
1260 	}
1261 }
1262 
1263 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1264 {
1265 	struct acpi_video_bus *video = device->video;
1266 	int i;
1267 
1268 	/*
1269 	 * If we have a broken _DOD or we have more than 8 output devices
1270 	 * under the graphics controller node that we can't proper deal with
1271 	 * in the operation region code currently, no need to test.
1272 	 */
1273 	if (!video->attached_count || video->child_count > 8)
1274 		return true;
1275 
1276 	for (i = 0; i < video->attached_count; i++) {
1277 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1278 		    (device->device_id & 0xfff))
1279 			return true;
1280 	}
1281 
1282 	return false;
1283 }
1284 
1285 /*
1286  *  Arg:
1287  *	video	: video bus device
1288  *
1289  *  Return:
1290  *	< 0	: error
1291  *
1292  *  Call _DOD to enumerate all devices attached to display adapter
1293  *
1294  */
1295 
1296 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1297 {
1298 	int status;
1299 	int count;
1300 	int i;
1301 	struct acpi_video_enumerated_device *active_list;
1302 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1303 	union acpi_object *dod = NULL;
1304 	union acpi_object *obj;
1305 
1306 	if (!video->cap._DOD)
1307 		return AE_NOT_EXIST;
1308 
1309 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1310 	if (ACPI_FAILURE(status)) {
1311 		acpi_handle_info(video->device->handle,
1312 				 "_DOD evaluation failed: %s\n",
1313 				 acpi_format_exception(status));
1314 		return status;
1315 	}
1316 
1317 	dod = buffer.pointer;
1318 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1319 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1320 		status = -EFAULT;
1321 		goto out;
1322 	}
1323 
1324 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1325 			  dod->package.count);
1326 
1327 	active_list = kcalloc(1 + dod->package.count,
1328 			      sizeof(struct acpi_video_enumerated_device),
1329 			      GFP_KERNEL);
1330 	if (!active_list) {
1331 		status = -ENOMEM;
1332 		goto out;
1333 	}
1334 
1335 	count = 0;
1336 	for (i = 0; i < dod->package.count; i++) {
1337 		obj = &dod->package.elements[i];
1338 
1339 		if (obj->type != ACPI_TYPE_INTEGER) {
1340 			acpi_handle_info(video->device->handle,
1341 					 "Invalid _DOD data in element %d\n", i);
1342 			continue;
1343 		}
1344 
1345 		active_list[count].value.int_val = obj->integer.value;
1346 		active_list[count].bind_info = NULL;
1347 
1348 		acpi_handle_debug(video->device->handle,
1349 				  "_DOD element[%d] = %d\n", i,
1350 				  (int)obj->integer.value);
1351 
1352 		count++;
1353 	}
1354 
1355 	kfree(video->attached_array);
1356 
1357 	video->attached_array = active_list;
1358 	video->attached_count = count;
1359 
1360 out:
1361 	kfree(buffer.pointer);
1362 	return status;
1363 }
1364 
1365 static int
1366 acpi_video_get_next_level(struct acpi_video_device *device,
1367 			  u32 level_current, u32 event)
1368 {
1369 	int min, max, min_above, max_below, i, l, delta = 255;
1370 	max = max_below = 0;
1371 	min = min_above = 255;
1372 	/* Find closest level to level_current */
1373 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1374 		l = device->brightness->levels[i];
1375 		if (abs(l - level_current) < abs(delta)) {
1376 			delta = l - level_current;
1377 			if (!delta)
1378 				break;
1379 		}
1380 	}
1381 	/* Adjust level_current to closest available level */
1382 	level_current += delta;
1383 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1384 		l = device->brightness->levels[i];
1385 		if (l < min)
1386 			min = l;
1387 		if (l > max)
1388 			max = l;
1389 		if (l < min_above && l > level_current)
1390 			min_above = l;
1391 		if (l > max_below && l < level_current)
1392 			max_below = l;
1393 	}
1394 
1395 	switch (event) {
1396 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1397 		return (level_current < max) ? min_above : min;
1398 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1399 		return (level_current < max) ? min_above : max;
1400 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1401 		return (level_current > min) ? max_below : min;
1402 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1403 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1404 		return 0;
1405 	default:
1406 		return level_current;
1407 	}
1408 }
1409 
1410 static void
1411 acpi_video_switch_brightness(struct work_struct *work)
1412 {
1413 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1414 			     struct acpi_video_device, switch_brightness_work);
1415 	unsigned long long level_current, level_next;
1416 	int event = device->switch_brightness_event;
1417 	int result = -EINVAL;
1418 
1419 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1420 	if (!device->backlight)
1421 		return;
1422 
1423 	if (!device->brightness)
1424 		goto out;
1425 
1426 	result = acpi_video_device_lcd_get_level_current(device,
1427 							 &level_current,
1428 							 false);
1429 	if (result)
1430 		goto out;
1431 
1432 	level_next = acpi_video_get_next_level(device, level_current, event);
1433 
1434 	result = acpi_video_device_lcd_set_level(device, level_next);
1435 
1436 	if (!result)
1437 		backlight_force_update(device->backlight,
1438 				       BACKLIGHT_UPDATE_HOTKEY);
1439 
1440 out:
1441 	if (result)
1442 		acpi_handle_info(device->dev->handle,
1443 				 "Failed to switch brightness\n");
1444 }
1445 
1446 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1447 			void **edid)
1448 {
1449 	struct acpi_video_bus *video;
1450 	struct acpi_video_device *video_device;
1451 	int i, length, ret;
1452 
1453 	if (!device || !acpi_driver_data(device))
1454 		return -EINVAL;
1455 
1456 	video = acpi_driver_data(device);
1457 
1458 	for (i = 0; i < video->attached_count; i++) {
1459 		video_device = video->attached_array[i].bind_info;
1460 
1461 		if (!video_device)
1462 			continue;
1463 
1464 		if (!video_device->cap._DDC)
1465 			continue;
1466 
1467 		if (type) {
1468 			switch (type) {
1469 			case ACPI_VIDEO_DISPLAY_CRT:
1470 				if (!video_device->flags.crt)
1471 					continue;
1472 				break;
1473 			case ACPI_VIDEO_DISPLAY_TV:
1474 				if (!video_device->flags.tvout)
1475 					continue;
1476 				break;
1477 			case ACPI_VIDEO_DISPLAY_DVI:
1478 				if (!video_device->flags.dvi)
1479 					continue;
1480 				break;
1481 			case ACPI_VIDEO_DISPLAY_LCD:
1482 				if (!video_device->flags.lcd)
1483 					continue;
1484 				break;
1485 			}
1486 		} else if (video_device->device_id != device_id) {
1487 			continue;
1488 		}
1489 
1490 		for (length = 512; length > 0; length -= 128) {
1491 			ret = acpi_video_device_EDID(video_device, edid, length);
1492 			if (ret > 0)
1493 				return ret;
1494 		}
1495 	}
1496 
1497 	return -ENODEV;
1498 }
1499 EXPORT_SYMBOL(acpi_video_get_edid);
1500 
1501 static int
1502 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1503 			   struct acpi_device *device)
1504 {
1505 	/*
1506 	 * There are systems where video module known to work fine regardless
1507 	 * of broken _DOD and ignoring returned value here doesn't cause
1508 	 * any issues later.
1509 	 */
1510 	acpi_video_device_enumerate(video);
1511 
1512 	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
1513 }
1514 
1515 /* acpi_video interface */
1516 
1517 /*
1518  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1519  * perform any automatic brightness change on receiving a notification.
1520  */
1521 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1522 {
1523 	return acpi_video_bus_DOS(video, 0,
1524 				  acpi_osi_is_win8() ? 1 : 0);
1525 }
1526 
1527 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1528 {
1529 	return acpi_video_bus_DOS(video, 0,
1530 				  acpi_osi_is_win8() ? 0 : 1);
1531 }
1532 
1533 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data)
1534 {
1535 	struct acpi_device *device = data;
1536 	struct acpi_video_bus *video = acpi_driver_data(device);
1537 	struct input_dev *input;
1538 	int keycode = 0;
1539 
1540 	if (!video || !video->input)
1541 		return;
1542 
1543 	input = video->input;
1544 
1545 	switch (event) {
1546 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1547 					 * most likely via hotkey. */
1548 		keycode = KEY_SWITCHVIDEOMODE;
1549 		break;
1550 
1551 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1552 					 * connector. */
1553 		acpi_video_device_enumerate(video);
1554 		acpi_video_device_rebind(video);
1555 		keycode = KEY_SWITCHVIDEOMODE;
1556 		break;
1557 
1558 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1559 		keycode = KEY_SWITCHVIDEOMODE;
1560 		break;
1561 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1562 		keycode = KEY_VIDEO_NEXT;
1563 		break;
1564 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1565 		keycode = KEY_VIDEO_PREV;
1566 		break;
1567 
1568 	default:
1569 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1570 				  event);
1571 		break;
1572 	}
1573 
1574 	if (acpi_notifier_call_chain(device, event, 0))
1575 		/* Something vetoed the keypress. */
1576 		keycode = 0;
1577 
1578 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1579 		input_report_key(input, keycode, 1);
1580 		input_sync(input);
1581 		input_report_key(input, keycode, 0);
1582 		input_sync(input);
1583 	}
1584 }
1585 
1586 static void brightness_switch_event(struct acpi_video_device *video_device,
1587 				    u32 event)
1588 {
1589 	if (!brightness_switch_enabled)
1590 		return;
1591 
1592 	video_device->switch_brightness_event = event;
1593 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1594 }
1595 
1596 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1597 {
1598 	struct acpi_video_device *video_device = data;
1599 	struct acpi_device *device = NULL;
1600 	struct acpi_video_bus *bus;
1601 	struct input_dev *input;
1602 	int keycode = 0;
1603 
1604 	if (!video_device)
1605 		return;
1606 
1607 	device = video_device->dev;
1608 	bus = video_device->video;
1609 	input = bus->input;
1610 
1611 	if (hw_changes_brightness > 0) {
1612 		if (video_device->backlight)
1613 			backlight_force_update(video_device->backlight,
1614 					       BACKLIGHT_UPDATE_HOTKEY);
1615 		acpi_notifier_call_chain(device, event, 0);
1616 		return;
1617 	}
1618 
1619 	switch (event) {
1620 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1621 		brightness_switch_event(video_device, event);
1622 		keycode = KEY_BRIGHTNESS_CYCLE;
1623 		break;
1624 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1625 		brightness_switch_event(video_device, event);
1626 		keycode = KEY_BRIGHTNESSUP;
1627 		break;
1628 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1629 		brightness_switch_event(video_device, event);
1630 		keycode = KEY_BRIGHTNESSDOWN;
1631 		break;
1632 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1633 		brightness_switch_event(video_device, event);
1634 		keycode = KEY_BRIGHTNESS_ZERO;
1635 		break;
1636 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1637 		brightness_switch_event(video_device, event);
1638 		keycode = KEY_DISPLAY_OFF;
1639 		break;
1640 	default:
1641 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1642 		break;
1643 	}
1644 
1645 	if (keycode)
1646 		may_report_brightness_keys = true;
1647 
1648 	acpi_notifier_call_chain(device, event, 0);
1649 
1650 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1651 		input_report_key(input, keycode, 1);
1652 		input_sync(input);
1653 		input_report_key(input, keycode, 0);
1654 		input_sync(input);
1655 	}
1656 }
1657 
1658 static int acpi_video_resume(struct notifier_block *nb,
1659 				unsigned long val, void *ign)
1660 {
1661 	struct acpi_video_bus *video;
1662 	struct acpi_video_device *video_device;
1663 	int i;
1664 
1665 	switch (val) {
1666 	case PM_POST_HIBERNATION:
1667 	case PM_POST_SUSPEND:
1668 	case PM_POST_RESTORE:
1669 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1670 
1671 		dev_info(&video->device->dev, "Restoring backlight state\n");
1672 
1673 		for (i = 0; i < video->attached_count; i++) {
1674 			video_device = video->attached_array[i].bind_info;
1675 			if (video_device && video_device->brightness)
1676 				acpi_video_device_lcd_set_level(video_device,
1677 						video_device->brightness->curr);
1678 		}
1679 
1680 		return NOTIFY_OK;
1681 	}
1682 	return NOTIFY_DONE;
1683 }
1684 
1685 static acpi_status
1686 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1687 			void **return_value)
1688 {
1689 	struct acpi_device *device = context;
1690 	struct acpi_device *sibling;
1691 
1692 	if (handle == device->handle)
1693 		return AE_CTRL_TERMINATE;
1694 
1695 	sibling = acpi_fetch_acpi_dev(handle);
1696 	if (!sibling)
1697 		return AE_OK;
1698 
1699 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1700 			return AE_ALREADY_EXISTS;
1701 
1702 	return AE_OK;
1703 }
1704 
1705 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1706 {
1707 	struct backlight_properties props;
1708 	struct pci_dev *pdev;
1709 	acpi_handle acpi_parent;
1710 	struct device *parent = NULL;
1711 	int result;
1712 	static int count;
1713 	char *name;
1714 
1715 	result = acpi_video_init_brightness(device);
1716 	if (result)
1717 		return;
1718 
1719 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1720 	if (!name)
1721 		return;
1722 	count++;
1723 
1724 	if (ACPI_SUCCESS(acpi_get_parent(device->dev->handle, &acpi_parent))) {
1725 		pdev = acpi_get_pci_dev(acpi_parent);
1726 		if (pdev) {
1727 			parent = &pdev->dev;
1728 			pci_dev_put(pdev);
1729 		}
1730 	}
1731 
1732 	memset(&props, 0, sizeof(struct backlight_properties));
1733 	props.type = BACKLIGHT_FIRMWARE;
1734 	props.max_brightness =
1735 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1736 	device->backlight = backlight_device_register(name,
1737 						      parent,
1738 						      device,
1739 						      &acpi_backlight_ops,
1740 						      &props);
1741 	kfree(name);
1742 	if (IS_ERR(device->backlight)) {
1743 		device->backlight = NULL;
1744 		return;
1745 	}
1746 
1747 	/*
1748 	 * Save current brightness level in case we have to restore it
1749 	 * before acpi_video_device_lcd_set_level() is called next time.
1750 	 */
1751 	device->backlight->props.brightness =
1752 			acpi_video_get_brightness(device->backlight);
1753 
1754 	device->cooling_dev = thermal_cooling_device_register("LCD", device,
1755 							      &video_cooling_ops);
1756 	if (IS_ERR(device->cooling_dev)) {
1757 		/*
1758 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1759 		 * Also, why the hell we are returning early and not attempt to
1760 		 * register video output if cooling device registration failed?
1761 		 * -- dtor
1762 		 */
1763 		device->cooling_dev = NULL;
1764 		return;
1765 	}
1766 
1767 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1768 		 device->cooling_dev->id);
1769 	result = sysfs_create_link(&device->dev->dev.kobj,
1770 			&device->cooling_dev->device.kobj,
1771 			"thermal_cooling");
1772 	if (result)
1773 		pr_info("sysfs link creation failed\n");
1774 
1775 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1776 			&device->dev->dev.kobj, "device");
1777 	if (result)
1778 		pr_info("Reverse sysfs link creation failed\n");
1779 }
1780 
1781 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1782 {
1783 	struct acpi_video_device *dev;
1784 	union acpi_object *levels;
1785 
1786 	mutex_lock(&video->device_list_lock);
1787 	list_for_each_entry(dev, &video->video_device_list, entry) {
1788 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1789 			kfree(levels);
1790 	}
1791 	mutex_unlock(&video->device_list_lock);
1792 }
1793 
1794 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1795 {
1796 	/*
1797 	 * Do not create backlight device for video output
1798 	 * device that is not in the enumerated list.
1799 	 */
1800 	if (!acpi_video_device_in_dod(dev)) {
1801 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1802 		return false;
1803 	}
1804 
1805 	if (only_lcd)
1806 		return dev->flags.lcd;
1807 	return true;
1808 }
1809 
1810 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1811 {
1812 	struct acpi_video_device *dev;
1813 
1814 	if (video->backlight_registered)
1815 		return 0;
1816 
1817 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1818 		return 0;
1819 
1820 	mutex_lock(&video->device_list_lock);
1821 	list_for_each_entry(dev, &video->video_device_list, entry) {
1822 		if (acpi_video_should_register_backlight(dev))
1823 			acpi_video_dev_register_backlight(dev);
1824 	}
1825 	mutex_unlock(&video->device_list_lock);
1826 
1827 	video->backlight_registered = true;
1828 
1829 	video->pm_nb.notifier_call = acpi_video_resume;
1830 	video->pm_nb.priority = 0;
1831 	return register_pm_notifier(&video->pm_nb);
1832 }
1833 
1834 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1835 {
1836 	if (device->backlight) {
1837 		backlight_device_unregister(device->backlight);
1838 		device->backlight = NULL;
1839 	}
1840 	if (device->brightness) {
1841 		kfree(device->brightness->levels);
1842 		kfree(device->brightness);
1843 		device->brightness = NULL;
1844 	}
1845 	if (device->cooling_dev) {
1846 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1847 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1848 		thermal_cooling_device_unregister(device->cooling_dev);
1849 		device->cooling_dev = NULL;
1850 	}
1851 }
1852 
1853 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1854 {
1855 	struct acpi_video_device *dev;
1856 	int error;
1857 
1858 	if (!video->backlight_registered)
1859 		return 0;
1860 
1861 	error = unregister_pm_notifier(&video->pm_nb);
1862 
1863 	mutex_lock(&video->device_list_lock);
1864 	list_for_each_entry(dev, &video->video_device_list, entry)
1865 		acpi_video_dev_unregister_backlight(dev);
1866 	mutex_unlock(&video->device_list_lock);
1867 
1868 	video->backlight_registered = false;
1869 
1870 	return error;
1871 }
1872 
1873 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1874 {
1875 	acpi_status status;
1876 	struct acpi_device *adev = device->dev;
1877 
1878 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1879 					     acpi_video_device_notify, device);
1880 	if (ACPI_FAILURE(status))
1881 		dev_err(&adev->dev, "Error installing notify handler\n");
1882 	else
1883 		device->flags.notify = 1;
1884 }
1885 
1886 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1887 {
1888 	struct input_dev *input;
1889 	struct acpi_video_device *dev;
1890 	int error;
1891 
1892 	video->input = input = input_allocate_device();
1893 	if (!input) {
1894 		error = -ENOMEM;
1895 		goto out;
1896 	}
1897 
1898 	error = acpi_video_bus_start_devices(video);
1899 	if (error)
1900 		goto err_free_input;
1901 
1902 	snprintf(video->phys, sizeof(video->phys),
1903 			"%s/video/input0", acpi_device_hid(video->device));
1904 
1905 	input->name = acpi_device_name(video->device);
1906 	input->phys = video->phys;
1907 	input->id.bustype = BUS_HOST;
1908 	input->id.product = 0x06;
1909 	input->dev.parent = &video->device->dev;
1910 	input->evbit[0] = BIT(EV_KEY);
1911 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1912 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1913 	set_bit(KEY_VIDEO_PREV, input->keybit);
1914 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1915 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1916 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1917 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1918 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1919 
1920 	error = input_register_device(input);
1921 	if (error)
1922 		goto err_stop_dev;
1923 
1924 	mutex_lock(&video->device_list_lock);
1925 	list_for_each_entry(dev, &video->video_device_list, entry)
1926 		acpi_video_dev_add_notify_handler(dev);
1927 	mutex_unlock(&video->device_list_lock);
1928 
1929 	return 0;
1930 
1931 err_stop_dev:
1932 	acpi_video_bus_stop_devices(video);
1933 err_free_input:
1934 	input_free_device(input);
1935 	video->input = NULL;
1936 out:
1937 	return error;
1938 }
1939 
1940 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1941 {
1942 	if (dev->flags.notify) {
1943 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1944 					   acpi_video_device_notify);
1945 		dev->flags.notify = 0;
1946 	}
1947 }
1948 
1949 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1950 {
1951 	struct acpi_video_device *dev;
1952 
1953 	mutex_lock(&video->device_list_lock);
1954 	list_for_each_entry(dev, &video->video_device_list, entry)
1955 		acpi_video_dev_remove_notify_handler(dev);
1956 	mutex_unlock(&video->device_list_lock);
1957 
1958 	acpi_video_bus_stop_devices(video);
1959 	input_unregister_device(video->input);
1960 	video->input = NULL;
1961 }
1962 
1963 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1964 {
1965 	struct acpi_video_device *dev, *next;
1966 
1967 	mutex_lock(&video->device_list_lock);
1968 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1969 		list_del(&dev->entry);
1970 		kfree(dev);
1971 	}
1972 	mutex_unlock(&video->device_list_lock);
1973 
1974 	return 0;
1975 }
1976 
1977 static int instance;
1978 
1979 static int acpi_video_bus_add(struct acpi_device *device)
1980 {
1981 	struct acpi_video_bus *video;
1982 	bool auto_detect;
1983 	int error;
1984 	acpi_status status;
1985 
1986 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1987 				acpi_dev_parent(device)->handle, 1,
1988 				acpi_video_bus_match, NULL,
1989 				device, NULL);
1990 	if (status == AE_ALREADY_EXISTS) {
1991 		pr_info(FW_BUG
1992 			"Duplicate ACPI video bus devices for the"
1993 			" same VGA controller, please try module "
1994 			"parameter \"video.allow_duplicates=1\""
1995 			"if the current driver doesn't work.\n");
1996 		if (!allow_duplicates)
1997 			return -ENODEV;
1998 	}
1999 
2000 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2001 	if (!video)
2002 		return -ENOMEM;
2003 
2004 	/* a hack to fix the duplicate name "VID" problem on T61 */
2005 	if (!strcmp(device->pnp.bus_id, "VID")) {
2006 		if (instance)
2007 			device->pnp.bus_id[3] = '0' + instance;
2008 		instance++;
2009 	}
2010 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2011 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2012 		if (instance)
2013 			device->pnp.bus_id[3] = '0' + instance;
2014 		instance++;
2015 	}
2016 
2017 	video->device = device;
2018 	strscpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2019 	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2020 	device->driver_data = video;
2021 
2022 	acpi_video_bus_find_cap(video);
2023 	error = acpi_video_bus_check(video);
2024 	if (error)
2025 		goto err_free_video;
2026 
2027 	mutex_init(&video->device_list_lock);
2028 	INIT_LIST_HEAD(&video->video_device_list);
2029 
2030 	error = acpi_video_bus_get_devices(video, device);
2031 	if (error)
2032 		goto err_put_video;
2033 
2034 	/*
2035 	 * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
2036 	 * evaluated to have functional panel brightness control.
2037 	 */
2038 	acpi_device_fix_up_power_children(device);
2039 
2040 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2041 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2042 	       video->flags.multihead ? "yes" : "no",
2043 	       video->flags.rom ? "yes" : "no",
2044 	       video->flags.post ? "yes" : "no");
2045 	mutex_lock(&video_list_lock);
2046 	list_add_tail(&video->entry, &video_bus_head);
2047 	mutex_unlock(&video_list_lock);
2048 
2049 	/*
2050 	 * If backlight-type auto-detection is used then a native backlight may
2051 	 * show up later and this may change the result from video to native.
2052 	 * Therefor normally the userspace visible /sys/class/backlight device
2053 	 * gets registered separately by the GPU driver calling
2054 	 * acpi_video_register_backlight() when an internal panel is detected.
2055 	 * Register the backlight now when not using auto-detection, so that
2056 	 * when the kernel cmdline or DMI-quirks are used the backlight will
2057 	 * get registered even if acpi_video_register_backlight() is not called.
2058 	 */
2059 	acpi_video_run_bcl_for_osi(video);
2060 	if (__acpi_video_get_backlight_type(false, &auto_detect) == acpi_backlight_video &&
2061 	    !auto_detect)
2062 		acpi_video_bus_register_backlight(video);
2063 
2064 	error = acpi_video_bus_add_notify_handler(video);
2065 	if (error)
2066 		goto err_del;
2067 
2068 	error = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
2069 						acpi_video_bus_notify, device);
2070 	if (error)
2071 		goto err_remove;
2072 
2073 	return 0;
2074 
2075 err_remove:
2076 	acpi_video_bus_remove_notify_handler(video);
2077 err_del:
2078 	mutex_lock(&video_list_lock);
2079 	list_del(&video->entry);
2080 	mutex_unlock(&video_list_lock);
2081 	acpi_video_bus_unregister_backlight(video);
2082 err_put_video:
2083 	acpi_video_bus_put_devices(video);
2084 	kfree(video->attached_array);
2085 err_free_video:
2086 	kfree(video);
2087 	device->driver_data = NULL;
2088 
2089 	return error;
2090 }
2091 
2092 static void acpi_video_bus_remove(struct acpi_device *device)
2093 {
2094 	struct acpi_video_bus *video = NULL;
2095 
2096 
2097 	if (!device || !acpi_driver_data(device))
2098 		return;
2099 
2100 	video = acpi_driver_data(device);
2101 
2102 	acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
2103 				       acpi_video_bus_notify);
2104 
2105 	mutex_lock(&video_list_lock);
2106 	list_del(&video->entry);
2107 	mutex_unlock(&video_list_lock);
2108 
2109 	acpi_video_bus_remove_notify_handler(video);
2110 	acpi_video_bus_unregister_backlight(video);
2111 	acpi_video_bus_put_devices(video);
2112 
2113 	kfree(video->attached_array);
2114 	kfree(video);
2115 }
2116 
2117 static int __init is_i740(struct pci_dev *dev)
2118 {
2119 	if (dev->device == 0x00D1)
2120 		return 1;
2121 	if (dev->device == 0x7000)
2122 		return 1;
2123 	return 0;
2124 }
2125 
2126 static int __init intel_opregion_present(void)
2127 {
2128 	int opregion = 0;
2129 	struct pci_dev *dev = NULL;
2130 	u32 address;
2131 
2132 	for_each_pci_dev(dev) {
2133 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2134 			continue;
2135 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2136 			continue;
2137 		/* We don't want to poke around undefined i740 registers */
2138 		if (is_i740(dev))
2139 			continue;
2140 		pci_read_config_dword(dev, 0xfc, &address);
2141 		if (!address)
2142 			continue;
2143 		opregion = 1;
2144 	}
2145 	return opregion;
2146 }
2147 
2148 int acpi_video_register(void)
2149 {
2150 	int ret = 0;
2151 
2152 	mutex_lock(&register_count_mutex);
2153 	if (register_count) {
2154 		/*
2155 		 * if the function of acpi_video_register is already called,
2156 		 * don't register the acpi_video_bus again and return no error.
2157 		 */
2158 		goto leave;
2159 	}
2160 
2161 	dmi_check_system(video_dmi_table);
2162 
2163 	ret = acpi_bus_register_driver(&acpi_video_bus);
2164 	if (ret)
2165 		goto leave;
2166 
2167 	/*
2168 	 * When the acpi_video_bus is loaded successfully, increase
2169 	 * the counter reference.
2170 	 */
2171 	register_count = 1;
2172 
2173 leave:
2174 	mutex_unlock(&register_count_mutex);
2175 	return ret;
2176 }
2177 EXPORT_SYMBOL(acpi_video_register);
2178 
2179 void acpi_video_unregister(void)
2180 {
2181 	mutex_lock(&register_count_mutex);
2182 	if (register_count) {
2183 		acpi_bus_unregister_driver(&acpi_video_bus);
2184 		register_count = 0;
2185 		may_report_brightness_keys = false;
2186 	}
2187 	mutex_unlock(&register_count_mutex);
2188 }
2189 EXPORT_SYMBOL(acpi_video_unregister);
2190 
2191 void acpi_video_register_backlight(void)
2192 {
2193 	struct acpi_video_bus *video;
2194 
2195 	mutex_lock(&video_list_lock);
2196 	list_for_each_entry(video, &video_bus_head, entry)
2197 		acpi_video_bus_register_backlight(video);
2198 	mutex_unlock(&video_list_lock);
2199 }
2200 EXPORT_SYMBOL(acpi_video_register_backlight);
2201 
2202 bool acpi_video_handles_brightness_key_presses(void)
2203 {
2204 	return may_report_brightness_keys &&
2205 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2206 }
2207 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2208 
2209 /*
2210  * This is kind of nasty. Hardware using Intel chipsets may require
2211  * the video opregion code to be run first in order to initialise
2212  * state before any ACPI video calls are made. To handle this we defer
2213  * registration of the video class until the opregion code has run.
2214  */
2215 
2216 static int __init acpi_video_init(void)
2217 {
2218 	/*
2219 	 * Let the module load even if ACPI is disabled (e.g. due to
2220 	 * a broken BIOS) so that i915.ko can still be loaded on such
2221 	 * old systems without an AcpiOpRegion.
2222 	 *
2223 	 * acpi_video_register() will report -ENODEV later as well due
2224 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2225 	 */
2226 	if (acpi_disabled)
2227 		return 0;
2228 
2229 	if (intel_opregion_present())
2230 		return 0;
2231 
2232 	return acpi_video_register();
2233 }
2234 
2235 static void __exit acpi_video_exit(void)
2236 {
2237 	acpi_video_unregister();
2238 }
2239 
2240 module_init(acpi_video_init);
2241 module_exit(acpi_video_exit);
2242