xref: /linux/drivers/acpi/acpi_video.c (revision 4b132aacb0768ac1e652cf517097ea6f237214b9)
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 static int
614 acpi_video_device_EDID(struct acpi_video_device *device,
615 		       union acpi_object **edid, int length)
616 {
617 	int status;
618 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
619 	union acpi_object *obj;
620 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
621 	struct acpi_object_list args = { 1, &arg0 };
622 
623 
624 	*edid = NULL;
625 
626 	if (!device)
627 		return -ENODEV;
628 	if (!length || (length % 128))
629 		return -EINVAL;
630 
631 	arg0.integer.value = length / 128;
632 
633 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
634 	if (ACPI_FAILURE(status))
635 		return -ENODEV;
636 
637 	obj = buffer.pointer;
638 
639 	if (obj && obj->type == ACPI_TYPE_BUFFER)
640 		*edid = obj;
641 	else {
642 		acpi_handle_debug(device->dev->handle,
643 				 "Invalid _DDC data for length %d\n", length);
644 		status = -EFAULT;
645 		kfree(obj);
646 	}
647 
648 	return status;
649 }
650 
651 /* bus */
652 
653 /*
654  *  Arg:
655  *	video		: video bus device pointer
656  *	bios_flag	:
657  *		0.	The system BIOS should NOT automatically switch(toggle)
658  *			the active display output.
659  *		1.	The system BIOS should automatically switch (toggle) the
660  *			active display output. No switch event.
661  *		2.	The _DGS value should be locked.
662  *		3.	The system BIOS should not automatically switch (toggle) the
663  *			active display output, but instead generate the display switch
664  *			event notify code.
665  *	lcd_flag	:
666  *		0.	The system BIOS should automatically control the brightness level
667  *			of the LCD when:
668  *			- the power changes from AC to DC (ACPI appendix B)
669  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
670  *		1.	The system BIOS should NOT automatically control the brightness
671  *			level of the LCD when:
672  *			- the power changes from AC to DC (ACPI appendix B)
673  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
674  *  Return Value:
675  *		-EINVAL	wrong arg.
676  */
677 
678 static int
679 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
680 {
681 	acpi_status status;
682 
683 	if (!video->cap._DOS)
684 		return 0;
685 
686 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
687 		return -EINVAL;
688 	video->dos_setting = (lcd_flag << 2) | bios_flag;
689 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
690 					    (lcd_flag << 2) | bios_flag);
691 	if (ACPI_FAILURE(status))
692 		return -EIO;
693 
694 	return 0;
695 }
696 
697 /*
698  * Simple comparison function used to sort backlight levels.
699  */
700 
701 static int
702 acpi_video_cmp_level(const void *a, const void *b)
703 {
704 	return *(int *)a - *(int *)b;
705 }
706 
707 /*
708  * Decides if _BQC/_BCQ for this system is usable
709  *
710  * We do this by changing the level first and then read out the current
711  * brightness level, if the value does not match, find out if it is using
712  * index. If not, clear the _BQC/_BCQ capability.
713  */
714 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
715 				int max_level, int current_level)
716 {
717 	struct acpi_video_device_brightness *br = device->brightness;
718 	int result;
719 	unsigned long long level;
720 	int test_level;
721 
722 	/* don't mess with existing known broken systems */
723 	if (bqc_offset_aml_bug_workaround)
724 		return 0;
725 
726 	/*
727 	 * Some systems always report current brightness level as maximum
728 	 * through _BQC, we need to test another value for them. However,
729 	 * there is a subtlety:
730 	 *
731 	 * If the _BCL package ordering is descending, the first level
732 	 * (br->levels[2]) is likely to be 0, and if the number of levels
733 	 * matches the number of steps, we might confuse a returned level to
734 	 * mean the index.
735 	 *
736 	 * For example:
737 	 *
738 	 *     current_level = max_level = 100
739 	 *     test_level = 0
740 	 *     returned level = 100
741 	 *
742 	 * In this case 100 means the level, not the index, and _BCM failed.
743 	 * Still, if the _BCL package ordering is descending, the index of
744 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
745 	 *
746 	 * This causes all _BQC calls to return bogus values causing weird
747 	 * behavior from the user's perspective.  For example:
748 	 *
749 	 * xbacklight -set 10; xbacklight -set 20;
750 	 *
751 	 * would flash to 90% and then slowly down to the desired level (20).
752 	 *
753 	 * The solution is simple; test anything other than the first level
754 	 * (e.g. 1).
755 	 */
756 	test_level = current_level == max_level
757 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
758 		: max_level;
759 
760 	result = acpi_video_device_lcd_set_level(device, test_level);
761 	if (result)
762 		return result;
763 
764 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
765 	if (result)
766 		return result;
767 
768 	if (level != test_level) {
769 		/* buggy _BQC found, need to find out if it uses index */
770 		if (level < br->count) {
771 			if (br->flags._BCL_reversed)
772 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
773 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
774 				br->flags._BQC_use_index = 1;
775 		}
776 
777 		if (!br->flags._BQC_use_index)
778 			device->cap._BQC = device->cap._BCQ = 0;
779 	}
780 
781 	return 0;
782 }
783 
784 int acpi_video_get_levels(struct acpi_device *device,
785 			  struct acpi_video_device_brightness **dev_br,
786 			  int *pmax_level)
787 {
788 	union acpi_object *obj = NULL;
789 	int i, max_level = 0, count = 0, level_ac_battery = 0;
790 	union acpi_object *o;
791 	struct acpi_video_device_brightness *br = NULL;
792 	int result = 0;
793 	u32 value;
794 
795 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
796 		acpi_handle_debug(device->handle,
797 				  "Could not query available LCD brightness level\n");
798 		result = -ENODEV;
799 		goto out;
800 	}
801 
802 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
803 		result = -EINVAL;
804 		goto out;
805 	}
806 
807 	br = kzalloc(sizeof(*br), GFP_KERNEL);
808 	if (!br) {
809 		result = -ENOMEM;
810 		goto out;
811 	}
812 
813 	/*
814 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
815 	 * in order to account for buggy BIOS which don't export the first two
816 	 * special levels (see below)
817 	 */
818 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
819 				   sizeof(*br->levels),
820 				   GFP_KERNEL);
821 	if (!br->levels) {
822 		result = -ENOMEM;
823 		goto out_free;
824 	}
825 
826 	for (i = 0; i < obj->package.count; i++) {
827 		o = (union acpi_object *)&obj->package.elements[i];
828 		if (o->type != ACPI_TYPE_INTEGER) {
829 			acpi_handle_info(device->handle, "Invalid data\n");
830 			continue;
831 		}
832 		value = (u32) o->integer.value;
833 		/* Skip duplicate entries */
834 		if (count > ACPI_VIDEO_FIRST_LEVEL
835 		    && br->levels[count - 1] == value)
836 			continue;
837 
838 		br->levels[count] = value;
839 
840 		if (br->levels[count] > max_level)
841 			max_level = br->levels[count];
842 		count++;
843 	}
844 
845 	/*
846 	 * some buggy BIOS don't export the levels
847 	 * when machine is on AC/Battery in _BCL package.
848 	 * In this case, the first two elements in _BCL packages
849 	 * are also supported brightness levels that OS should take care of.
850 	 */
851 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
852 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
853 			level_ac_battery++;
854 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
855 			level_ac_battery++;
856 	}
857 
858 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
859 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
860 		br->flags._BCL_no_ac_battery_levels = 1;
861 		for (i = (count - 1 + level_ac_battery);
862 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
863 			br->levels[i] = br->levels[i - level_ac_battery];
864 		count += level_ac_battery;
865 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
866 		acpi_handle_info(device->handle,
867 				 "Too many duplicates in _BCL package");
868 
869 	/* Check if the _BCL package is in a reversed order */
870 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
871 		br->flags._BCL_reversed = 1;
872 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
873 		     count - ACPI_VIDEO_FIRST_LEVEL,
874 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
875 		     acpi_video_cmp_level, NULL);
876 	} else if (max_level != br->levels[count - 1])
877 		acpi_handle_info(device->handle,
878 				 "Found unordered _BCL package");
879 
880 	br->count = count;
881 	*dev_br = br;
882 	if (pmax_level)
883 		*pmax_level = max_level;
884 
885 out:
886 	kfree(obj);
887 	return result;
888 out_free:
889 	kfree(br);
890 	goto out;
891 }
892 EXPORT_SYMBOL(acpi_video_get_levels);
893 
894 /*
895  *  Arg:
896  *	device	: video output device (LCD, CRT, ..)
897  *
898  *  Return Value:
899  *	Maximum brightness level
900  *
901  *  Allocate and initialize device->brightness.
902  */
903 
904 static int
905 acpi_video_init_brightness(struct acpi_video_device *device)
906 {
907 	int i, max_level = 0;
908 	unsigned long long level, level_old;
909 	struct acpi_video_device_brightness *br = NULL;
910 	int result;
911 
912 	result = acpi_video_get_levels(device->dev, &br, &max_level);
913 	if (result)
914 		return result;
915 	device->brightness = br;
916 
917 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
918 	br->curr = level = max_level;
919 
920 	if (!device->cap._BQC)
921 		goto set_level;
922 
923 	result = acpi_video_device_lcd_get_level_current(device,
924 							 &level_old, true);
925 	if (result)
926 		goto out_free_levels;
927 
928 	result = acpi_video_bqc_quirk(device, max_level, level_old);
929 	if (result)
930 		goto out_free_levels;
931 	/*
932 	 * cap._BQC may get cleared due to _BQC is found to be broken
933 	 * in acpi_video_bqc_quirk, so check again here.
934 	 */
935 	if (!device->cap._BQC)
936 		goto set_level;
937 
938 	level = acpi_video_bqc_value_to_level(device, level_old);
939 	/*
940 	 * On some buggy laptops, _BQC returns an uninitialized
941 	 * value when invoked for the first time, i.e.
942 	 * level_old is invalid (no matter whether it's a level
943 	 * or an index). Set the backlight to max_level in this case.
944 	 */
945 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
946 		if (level == br->levels[i])
947 			break;
948 	if (i == br->count || !level)
949 		level = max_level;
950 
951 set_level:
952 	result = acpi_video_device_lcd_set_level(device, level);
953 	if (result)
954 		goto out_free_levels;
955 
956 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
957 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
958 
959 	return 0;
960 
961 out_free_levels:
962 	kfree(br->levels);
963 	kfree(br);
964 	device->brightness = NULL;
965 	return result;
966 }
967 
968 /*
969  *  Arg:
970  *	device	: video output device (LCD, CRT, ..)
971  *
972  *  Return Value:
973  *	None
974  *
975  *  Find out all required AML methods defined under the output
976  *  device.
977  */
978 
979 static void acpi_video_device_find_cap(struct acpi_video_device *device)
980 {
981 	if (acpi_has_method(device->dev->handle, "_ADR"))
982 		device->cap._ADR = 1;
983 	if (acpi_has_method(device->dev->handle, "_BCL"))
984 		device->cap._BCL = 1;
985 	if (acpi_has_method(device->dev->handle, "_BCM"))
986 		device->cap._BCM = 1;
987 	if (acpi_has_method(device->dev->handle, "_BQC")) {
988 		device->cap._BQC = 1;
989 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
990 		acpi_handle_info(device->dev->handle,
991 				 "_BCQ is used instead of _BQC\n");
992 		device->cap._BCQ = 1;
993 	}
994 
995 	if (acpi_has_method(device->dev->handle, "_DDC"))
996 		device->cap._DDC = 1;
997 }
998 
999 /*
1000  *  Arg:
1001  *	device	: video output device (VGA)
1002  *
1003  *  Return Value:
1004  *	None
1005  *
1006  *  Find out all required AML methods defined under the video bus device.
1007  */
1008 
1009 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1010 {
1011 	if (acpi_has_method(video->device->handle, "_DOS"))
1012 		video->cap._DOS = 1;
1013 	if (acpi_has_method(video->device->handle, "_DOD"))
1014 		video->cap._DOD = 1;
1015 	if (acpi_has_method(video->device->handle, "_ROM"))
1016 		video->cap._ROM = 1;
1017 	if (acpi_has_method(video->device->handle, "_GPD"))
1018 		video->cap._GPD = 1;
1019 	if (acpi_has_method(video->device->handle, "_SPD"))
1020 		video->cap._SPD = 1;
1021 	if (acpi_has_method(video->device->handle, "_VPO"))
1022 		video->cap._VPO = 1;
1023 }
1024 
1025 /*
1026  * Check whether the video bus device has required AML method to
1027  * support the desired features
1028  */
1029 
1030 static int acpi_video_bus_check(struct acpi_video_bus *video)
1031 {
1032 	acpi_status status = -ENOENT;
1033 	struct pci_dev *dev;
1034 
1035 	if (!video)
1036 		return -EINVAL;
1037 
1038 	dev = acpi_get_pci_dev(video->device->handle);
1039 	if (!dev)
1040 		return -ENODEV;
1041 	pci_dev_put(dev);
1042 
1043 	/*
1044 	 * Since there is no HID, CID and so on for VGA driver, we have
1045 	 * to check well known required nodes.
1046 	 */
1047 
1048 	/* Does this device support video switching? */
1049 	if (video->cap._DOS || video->cap._DOD) {
1050 		if (!video->cap._DOS) {
1051 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1052 				acpi_device_bid(video->device));
1053 		}
1054 		video->flags.multihead = 1;
1055 		status = 0;
1056 	}
1057 
1058 	/* Does this device support retrieving a video ROM? */
1059 	if (video->cap._ROM) {
1060 		video->flags.rom = 1;
1061 		status = 0;
1062 	}
1063 
1064 	/* Does this device support configuring which video device to POST? */
1065 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1066 		video->flags.post = 1;
1067 		status = 0;
1068 	}
1069 
1070 	return status;
1071 }
1072 
1073 /*
1074  * --------------------------------------------------------------------------
1075  *                               Driver Interface
1076  * --------------------------------------------------------------------------
1077  */
1078 
1079 /* device interface */
1080 static struct acpi_video_device_attrib *
1081 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1082 {
1083 	struct acpi_video_enumerated_device *ids;
1084 	int i;
1085 
1086 	for (i = 0; i < video->attached_count; i++) {
1087 		ids = &video->attached_array[i];
1088 		if ((ids->value.int_val & 0xffff) == device_id)
1089 			return &ids->value.attrib;
1090 	}
1091 
1092 	return NULL;
1093 }
1094 
1095 static int
1096 acpi_video_get_device_type(struct acpi_video_bus *video,
1097 			   unsigned long device_id)
1098 {
1099 	struct acpi_video_enumerated_device *ids;
1100 	int i;
1101 
1102 	for (i = 0; i < video->attached_count; i++) {
1103 		ids = &video->attached_array[i];
1104 		if ((ids->value.int_val & 0xffff) == device_id)
1105 			return ids->value.int_val;
1106 	}
1107 
1108 	return 0;
1109 }
1110 
1111 static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
1112 {
1113 	struct acpi_video_bus *video = arg;
1114 	struct acpi_video_device_attrib *attribute;
1115 	struct acpi_video_device *data;
1116 	unsigned long long device_id;
1117 	acpi_status status;
1118 	int device_type;
1119 
1120 	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1121 	/* Skip devices without _ADR instead of failing. */
1122 	if (ACPI_FAILURE(status))
1123 		goto exit;
1124 
1125 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1126 	if (!data) {
1127 		dev_dbg(&device->dev, "Cannot attach\n");
1128 		return -ENOMEM;
1129 	}
1130 
1131 	strscpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1132 	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1133 
1134 	data->device_id = device_id;
1135 	data->video = video;
1136 	data->dev = device;
1137 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1138 			  acpi_video_switch_brightness);
1139 
1140 	attribute = acpi_video_get_device_attr(video, device_id);
1141 
1142 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1143 		switch (attribute->display_type) {
1144 		case ACPI_VIDEO_DISPLAY_CRT:
1145 			data->flags.crt = 1;
1146 			break;
1147 		case ACPI_VIDEO_DISPLAY_TV:
1148 			data->flags.tvout = 1;
1149 			break;
1150 		case ACPI_VIDEO_DISPLAY_DVI:
1151 			data->flags.dvi = 1;
1152 			break;
1153 		case ACPI_VIDEO_DISPLAY_LCD:
1154 			data->flags.lcd = 1;
1155 			break;
1156 		default:
1157 			data->flags.unknown = 1;
1158 			break;
1159 		}
1160 		if (attribute->bios_can_detect)
1161 			data->flags.bios = 1;
1162 	} else {
1163 		/* Check for legacy IDs */
1164 		device_type = acpi_video_get_device_type(video, device_id);
1165 		/* Ignore bits 16 and 18-20 */
1166 		switch (device_type & 0xffe2ffff) {
1167 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1168 			data->flags.crt = 1;
1169 			break;
1170 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1171 			data->flags.lcd = 1;
1172 			break;
1173 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1174 			data->flags.tvout = 1;
1175 			break;
1176 		default:
1177 			data->flags.unknown = 1;
1178 		}
1179 	}
1180 
1181 	acpi_video_device_bind(video, data);
1182 	acpi_video_device_find_cap(data);
1183 
1184 	if (data->cap._BCM && data->cap._BCL)
1185 		may_report_brightness_keys = true;
1186 
1187 	mutex_lock(&video->device_list_lock);
1188 	list_add_tail(&data->entry, &video->video_device_list);
1189 	mutex_unlock(&video->device_list_lock);
1190 
1191 exit:
1192 	video->child_count++;
1193 	return 0;
1194 }
1195 
1196 /*
1197  *  Arg:
1198  *	video	: video bus device
1199  *
1200  *  Return:
1201  *	none
1202  *
1203  *  Enumerate the video device list of the video bus,
1204  *  bind the ids with the corresponding video devices
1205  *  under the video bus.
1206  */
1207 
1208 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1209 {
1210 	struct acpi_video_device *dev;
1211 
1212 	mutex_lock(&video->device_list_lock);
1213 
1214 	list_for_each_entry(dev, &video->video_device_list, entry)
1215 		acpi_video_device_bind(video, dev);
1216 
1217 	mutex_unlock(&video->device_list_lock);
1218 }
1219 
1220 /*
1221  *  Arg:
1222  *	video	: video bus device
1223  *	device	: video output device under the video
1224  *		bus
1225  *
1226  *  Return:
1227  *	none
1228  *
1229  *  Bind the ids with the corresponding video devices
1230  *  under the video bus.
1231  */
1232 
1233 static void
1234 acpi_video_device_bind(struct acpi_video_bus *video,
1235 		       struct acpi_video_device *device)
1236 {
1237 	struct acpi_video_enumerated_device *ids;
1238 	int i;
1239 
1240 	for (i = 0; i < video->attached_count; i++) {
1241 		ids = &video->attached_array[i];
1242 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1243 			ids->bind_info = device;
1244 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1245 					  __func__, i);
1246 		}
1247 	}
1248 }
1249 
1250 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1251 {
1252 	struct acpi_video_bus *video = device->video;
1253 	int i;
1254 
1255 	/*
1256 	 * If we have a broken _DOD or we have more than 8 output devices
1257 	 * under the graphics controller node that we can't proper deal with
1258 	 * in the operation region code currently, no need to test.
1259 	 */
1260 	if (!video->attached_count || video->child_count > 8)
1261 		return true;
1262 
1263 	for (i = 0; i < video->attached_count; i++) {
1264 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1265 		    (device->device_id & 0xfff))
1266 			return true;
1267 	}
1268 
1269 	return false;
1270 }
1271 
1272 /*
1273  *  Arg:
1274  *	video	: video bus device
1275  *
1276  *  Return:
1277  *	< 0	: error
1278  *
1279  *  Call _DOD to enumerate all devices attached to display adapter
1280  *
1281  */
1282 
1283 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1284 {
1285 	int status;
1286 	int count;
1287 	int i;
1288 	struct acpi_video_enumerated_device *active_list;
1289 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1290 	union acpi_object *dod = NULL;
1291 	union acpi_object *obj;
1292 
1293 	if (!video->cap._DOD)
1294 		return AE_NOT_EXIST;
1295 
1296 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1297 	if (ACPI_FAILURE(status)) {
1298 		acpi_handle_info(video->device->handle,
1299 				 "_DOD evaluation failed: %s\n",
1300 				 acpi_format_exception(status));
1301 		return status;
1302 	}
1303 
1304 	dod = buffer.pointer;
1305 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1306 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1307 		status = -EFAULT;
1308 		goto out;
1309 	}
1310 
1311 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1312 			  dod->package.count);
1313 
1314 	active_list = kcalloc(1 + dod->package.count,
1315 			      sizeof(struct acpi_video_enumerated_device),
1316 			      GFP_KERNEL);
1317 	if (!active_list) {
1318 		status = -ENOMEM;
1319 		goto out;
1320 	}
1321 
1322 	count = 0;
1323 	for (i = 0; i < dod->package.count; i++) {
1324 		obj = &dod->package.elements[i];
1325 
1326 		if (obj->type != ACPI_TYPE_INTEGER) {
1327 			acpi_handle_info(video->device->handle,
1328 					 "Invalid _DOD data in element %d\n", i);
1329 			continue;
1330 		}
1331 
1332 		active_list[count].value.int_val = obj->integer.value;
1333 		active_list[count].bind_info = NULL;
1334 
1335 		acpi_handle_debug(video->device->handle,
1336 				  "_DOD element[%d] = %d\n", i,
1337 				  (int)obj->integer.value);
1338 
1339 		count++;
1340 	}
1341 
1342 	kfree(video->attached_array);
1343 
1344 	video->attached_array = active_list;
1345 	video->attached_count = count;
1346 
1347 out:
1348 	kfree(buffer.pointer);
1349 	return status;
1350 }
1351 
1352 static int
1353 acpi_video_get_next_level(struct acpi_video_device *device,
1354 			  u32 level_current, u32 event)
1355 {
1356 	int min, max, min_above, max_below, i, l, delta = 255;
1357 	max = max_below = 0;
1358 	min = min_above = 255;
1359 	/* Find closest level to level_current */
1360 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1361 		l = device->brightness->levels[i];
1362 		if (abs(l - level_current) < abs(delta)) {
1363 			delta = l - level_current;
1364 			if (!delta)
1365 				break;
1366 		}
1367 	}
1368 	/* Adjust level_current to closest available level */
1369 	level_current += delta;
1370 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1371 		l = device->brightness->levels[i];
1372 		if (l < min)
1373 			min = l;
1374 		if (l > max)
1375 			max = l;
1376 		if (l < min_above && l > level_current)
1377 			min_above = l;
1378 		if (l > max_below && l < level_current)
1379 			max_below = l;
1380 	}
1381 
1382 	switch (event) {
1383 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1384 		return (level_current < max) ? min_above : min;
1385 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1386 		return (level_current < max) ? min_above : max;
1387 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1388 		return (level_current > min) ? max_below : min;
1389 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1390 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1391 		return 0;
1392 	default:
1393 		return level_current;
1394 	}
1395 }
1396 
1397 static void
1398 acpi_video_switch_brightness(struct work_struct *work)
1399 {
1400 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1401 			     struct acpi_video_device, switch_brightness_work);
1402 	unsigned long long level_current, level_next;
1403 	int event = device->switch_brightness_event;
1404 	int result = -EINVAL;
1405 
1406 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1407 	if (!device->backlight)
1408 		return;
1409 
1410 	if (!device->brightness)
1411 		goto out;
1412 
1413 	result = acpi_video_device_lcd_get_level_current(device,
1414 							 &level_current,
1415 							 false);
1416 	if (result)
1417 		goto out;
1418 
1419 	level_next = acpi_video_get_next_level(device, level_current, event);
1420 
1421 	result = acpi_video_device_lcd_set_level(device, level_next);
1422 
1423 	if (!result)
1424 		backlight_force_update(device->backlight,
1425 				       BACKLIGHT_UPDATE_HOTKEY);
1426 
1427 out:
1428 	if (result)
1429 		acpi_handle_info(device->dev->handle,
1430 				 "Failed to switch brightness\n");
1431 }
1432 
1433 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1434 			void **edid)
1435 {
1436 	struct acpi_video_bus *video;
1437 	struct acpi_video_device *video_device;
1438 	union acpi_object *buffer = NULL;
1439 	acpi_status status;
1440 	int i, length;
1441 
1442 	if (!device || !acpi_driver_data(device))
1443 		return -EINVAL;
1444 
1445 	video = acpi_driver_data(device);
1446 
1447 	for (i = 0; i < video->attached_count; i++) {
1448 		video_device = video->attached_array[i].bind_info;
1449 
1450 		if (!video_device)
1451 			continue;
1452 
1453 		if (!video_device->cap._DDC)
1454 			continue;
1455 
1456 		if (type) {
1457 			switch (type) {
1458 			case ACPI_VIDEO_DISPLAY_CRT:
1459 				if (!video_device->flags.crt)
1460 					continue;
1461 				break;
1462 			case ACPI_VIDEO_DISPLAY_TV:
1463 				if (!video_device->flags.tvout)
1464 					continue;
1465 				break;
1466 			case ACPI_VIDEO_DISPLAY_DVI:
1467 				if (!video_device->flags.dvi)
1468 					continue;
1469 				break;
1470 			case ACPI_VIDEO_DISPLAY_LCD:
1471 				if (!video_device->flags.lcd)
1472 					continue;
1473 				break;
1474 			}
1475 		} else if (video_device->device_id != device_id) {
1476 			continue;
1477 		}
1478 
1479 		for (length = 512; length > 0; length -= 128) {
1480 			status = acpi_video_device_EDID(video_device, &buffer,
1481 							length);
1482 			if (ACPI_SUCCESS(status))
1483 				break;
1484 		}
1485 		if (!length)
1486 			continue;
1487 
1488 		*edid = buffer->buffer.pointer;
1489 		return length;
1490 	}
1491 
1492 	return -ENODEV;
1493 }
1494 EXPORT_SYMBOL(acpi_video_get_edid);
1495 
1496 static int
1497 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1498 			   struct acpi_device *device)
1499 {
1500 	/*
1501 	 * There are systems where video module known to work fine regardless
1502 	 * of broken _DOD and ignoring returned value here doesn't cause
1503 	 * any issues later.
1504 	 */
1505 	acpi_video_device_enumerate(video);
1506 
1507 	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
1508 }
1509 
1510 /* acpi_video interface */
1511 
1512 /*
1513  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1514  * perform any automatic brightness change on receiving a notification.
1515  */
1516 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1517 {
1518 	return acpi_video_bus_DOS(video, 0,
1519 				  acpi_osi_is_win8() ? 1 : 0);
1520 }
1521 
1522 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1523 {
1524 	return acpi_video_bus_DOS(video, 0,
1525 				  acpi_osi_is_win8() ? 0 : 1);
1526 }
1527 
1528 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data)
1529 {
1530 	struct acpi_device *device = data;
1531 	struct acpi_video_bus *video = acpi_driver_data(device);
1532 	struct input_dev *input;
1533 	int keycode = 0;
1534 
1535 	if (!video || !video->input)
1536 		return;
1537 
1538 	input = video->input;
1539 
1540 	switch (event) {
1541 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1542 					 * most likely via hotkey. */
1543 		keycode = KEY_SWITCHVIDEOMODE;
1544 		break;
1545 
1546 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1547 					 * connector. */
1548 		acpi_video_device_enumerate(video);
1549 		acpi_video_device_rebind(video);
1550 		keycode = KEY_SWITCHVIDEOMODE;
1551 		break;
1552 
1553 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1554 		keycode = KEY_SWITCHVIDEOMODE;
1555 		break;
1556 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1557 		keycode = KEY_VIDEO_NEXT;
1558 		break;
1559 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1560 		keycode = KEY_VIDEO_PREV;
1561 		break;
1562 
1563 	default:
1564 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1565 				  event);
1566 		break;
1567 	}
1568 
1569 	if (acpi_notifier_call_chain(device, event, 0))
1570 		/* Something vetoed the keypress. */
1571 		keycode = 0;
1572 
1573 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1574 		input_report_key(input, keycode, 1);
1575 		input_sync(input);
1576 		input_report_key(input, keycode, 0);
1577 		input_sync(input);
1578 	}
1579 }
1580 
1581 static void brightness_switch_event(struct acpi_video_device *video_device,
1582 				    u32 event)
1583 {
1584 	if (!brightness_switch_enabled)
1585 		return;
1586 
1587 	video_device->switch_brightness_event = event;
1588 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1589 }
1590 
1591 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1592 {
1593 	struct acpi_video_device *video_device = data;
1594 	struct acpi_device *device = NULL;
1595 	struct acpi_video_bus *bus;
1596 	struct input_dev *input;
1597 	int keycode = 0;
1598 
1599 	if (!video_device)
1600 		return;
1601 
1602 	device = video_device->dev;
1603 	bus = video_device->video;
1604 	input = bus->input;
1605 
1606 	if (hw_changes_brightness > 0) {
1607 		if (video_device->backlight)
1608 			backlight_force_update(video_device->backlight,
1609 					       BACKLIGHT_UPDATE_HOTKEY);
1610 		acpi_notifier_call_chain(device, event, 0);
1611 		return;
1612 	}
1613 
1614 	switch (event) {
1615 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1616 		brightness_switch_event(video_device, event);
1617 		keycode = KEY_BRIGHTNESS_CYCLE;
1618 		break;
1619 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1620 		brightness_switch_event(video_device, event);
1621 		keycode = KEY_BRIGHTNESSUP;
1622 		break;
1623 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1624 		brightness_switch_event(video_device, event);
1625 		keycode = KEY_BRIGHTNESSDOWN;
1626 		break;
1627 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1628 		brightness_switch_event(video_device, event);
1629 		keycode = KEY_BRIGHTNESS_ZERO;
1630 		break;
1631 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1632 		brightness_switch_event(video_device, event);
1633 		keycode = KEY_DISPLAY_OFF;
1634 		break;
1635 	default:
1636 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1637 		break;
1638 	}
1639 
1640 	if (keycode)
1641 		may_report_brightness_keys = true;
1642 
1643 	acpi_notifier_call_chain(device, event, 0);
1644 
1645 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1646 		input_report_key(input, keycode, 1);
1647 		input_sync(input);
1648 		input_report_key(input, keycode, 0);
1649 		input_sync(input);
1650 	}
1651 }
1652 
1653 static int acpi_video_resume(struct notifier_block *nb,
1654 				unsigned long val, void *ign)
1655 {
1656 	struct acpi_video_bus *video;
1657 	struct acpi_video_device *video_device;
1658 	int i;
1659 
1660 	switch (val) {
1661 	case PM_POST_HIBERNATION:
1662 	case PM_POST_SUSPEND:
1663 	case PM_POST_RESTORE:
1664 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1665 
1666 		dev_info(&video->device->dev, "Restoring backlight state\n");
1667 
1668 		for (i = 0; i < video->attached_count; i++) {
1669 			video_device = video->attached_array[i].bind_info;
1670 			if (video_device && video_device->brightness)
1671 				acpi_video_device_lcd_set_level(video_device,
1672 						video_device->brightness->curr);
1673 		}
1674 
1675 		return NOTIFY_OK;
1676 	}
1677 	return NOTIFY_DONE;
1678 }
1679 
1680 static acpi_status
1681 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1682 			void **return_value)
1683 {
1684 	struct acpi_device *device = context;
1685 	struct acpi_device *sibling;
1686 
1687 	if (handle == device->handle)
1688 		return AE_CTRL_TERMINATE;
1689 
1690 	sibling = acpi_fetch_acpi_dev(handle);
1691 	if (!sibling)
1692 		return AE_OK;
1693 
1694 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1695 			return AE_ALREADY_EXISTS;
1696 
1697 	return AE_OK;
1698 }
1699 
1700 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1701 {
1702 	struct backlight_properties props;
1703 	struct pci_dev *pdev;
1704 	acpi_handle acpi_parent;
1705 	struct device *parent = NULL;
1706 	int result;
1707 	static int count;
1708 	char *name;
1709 
1710 	result = acpi_video_init_brightness(device);
1711 	if (result)
1712 		return;
1713 
1714 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1715 	if (!name)
1716 		return;
1717 	count++;
1718 
1719 	if (ACPI_SUCCESS(acpi_get_parent(device->dev->handle, &acpi_parent))) {
1720 		pdev = acpi_get_pci_dev(acpi_parent);
1721 		if (pdev) {
1722 			parent = &pdev->dev;
1723 			pci_dev_put(pdev);
1724 		}
1725 	}
1726 
1727 	memset(&props, 0, sizeof(struct backlight_properties));
1728 	props.type = BACKLIGHT_FIRMWARE;
1729 	props.max_brightness =
1730 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1731 	device->backlight = backlight_device_register(name,
1732 						      parent,
1733 						      device,
1734 						      &acpi_backlight_ops,
1735 						      &props);
1736 	kfree(name);
1737 	if (IS_ERR(device->backlight)) {
1738 		device->backlight = NULL;
1739 		return;
1740 	}
1741 
1742 	/*
1743 	 * Save current brightness level in case we have to restore it
1744 	 * before acpi_video_device_lcd_set_level() is called next time.
1745 	 */
1746 	device->backlight->props.brightness =
1747 			acpi_video_get_brightness(device->backlight);
1748 
1749 	device->cooling_dev = thermal_cooling_device_register("LCD", device,
1750 							      &video_cooling_ops);
1751 	if (IS_ERR(device->cooling_dev)) {
1752 		/*
1753 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1754 		 * Also, why the hell we are returning early and not attempt to
1755 		 * register video output if cooling device registration failed?
1756 		 * -- dtor
1757 		 */
1758 		device->cooling_dev = NULL;
1759 		return;
1760 	}
1761 
1762 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1763 		 device->cooling_dev->id);
1764 	result = sysfs_create_link(&device->dev->dev.kobj,
1765 			&device->cooling_dev->device.kobj,
1766 			"thermal_cooling");
1767 	if (result)
1768 		pr_info("sysfs link creation failed\n");
1769 
1770 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1771 			&device->dev->dev.kobj, "device");
1772 	if (result)
1773 		pr_info("Reverse sysfs link creation failed\n");
1774 }
1775 
1776 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1777 {
1778 	struct acpi_video_device *dev;
1779 	union acpi_object *levels;
1780 
1781 	mutex_lock(&video->device_list_lock);
1782 	list_for_each_entry(dev, &video->video_device_list, entry) {
1783 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1784 			kfree(levels);
1785 	}
1786 	mutex_unlock(&video->device_list_lock);
1787 }
1788 
1789 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1790 {
1791 	/*
1792 	 * Do not create backlight device for video output
1793 	 * device that is not in the enumerated list.
1794 	 */
1795 	if (!acpi_video_device_in_dod(dev)) {
1796 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1797 		return false;
1798 	}
1799 
1800 	if (only_lcd)
1801 		return dev->flags.lcd;
1802 	return true;
1803 }
1804 
1805 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1806 {
1807 	struct acpi_video_device *dev;
1808 
1809 	if (video->backlight_registered)
1810 		return 0;
1811 
1812 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1813 		return 0;
1814 
1815 	mutex_lock(&video->device_list_lock);
1816 	list_for_each_entry(dev, &video->video_device_list, entry) {
1817 		if (acpi_video_should_register_backlight(dev))
1818 			acpi_video_dev_register_backlight(dev);
1819 	}
1820 	mutex_unlock(&video->device_list_lock);
1821 
1822 	video->backlight_registered = true;
1823 
1824 	video->pm_nb.notifier_call = acpi_video_resume;
1825 	video->pm_nb.priority = 0;
1826 	return register_pm_notifier(&video->pm_nb);
1827 }
1828 
1829 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1830 {
1831 	if (device->backlight) {
1832 		backlight_device_unregister(device->backlight);
1833 		device->backlight = NULL;
1834 	}
1835 	if (device->brightness) {
1836 		kfree(device->brightness->levels);
1837 		kfree(device->brightness);
1838 		device->brightness = NULL;
1839 	}
1840 	if (device->cooling_dev) {
1841 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1842 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1843 		thermal_cooling_device_unregister(device->cooling_dev);
1844 		device->cooling_dev = NULL;
1845 	}
1846 }
1847 
1848 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1849 {
1850 	struct acpi_video_device *dev;
1851 	int error;
1852 
1853 	if (!video->backlight_registered)
1854 		return 0;
1855 
1856 	error = unregister_pm_notifier(&video->pm_nb);
1857 
1858 	mutex_lock(&video->device_list_lock);
1859 	list_for_each_entry(dev, &video->video_device_list, entry)
1860 		acpi_video_dev_unregister_backlight(dev);
1861 	mutex_unlock(&video->device_list_lock);
1862 
1863 	video->backlight_registered = false;
1864 
1865 	return error;
1866 }
1867 
1868 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1869 {
1870 	acpi_status status;
1871 	struct acpi_device *adev = device->dev;
1872 
1873 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1874 					     acpi_video_device_notify, device);
1875 	if (ACPI_FAILURE(status))
1876 		dev_err(&adev->dev, "Error installing notify handler\n");
1877 	else
1878 		device->flags.notify = 1;
1879 }
1880 
1881 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1882 {
1883 	struct input_dev *input;
1884 	struct acpi_video_device *dev;
1885 	int error;
1886 
1887 	video->input = input = input_allocate_device();
1888 	if (!input) {
1889 		error = -ENOMEM;
1890 		goto out;
1891 	}
1892 
1893 	error = acpi_video_bus_start_devices(video);
1894 	if (error)
1895 		goto err_free_input;
1896 
1897 	snprintf(video->phys, sizeof(video->phys),
1898 			"%s/video/input0", acpi_device_hid(video->device));
1899 
1900 	input->name = acpi_device_name(video->device);
1901 	input->phys = video->phys;
1902 	input->id.bustype = BUS_HOST;
1903 	input->id.product = 0x06;
1904 	input->dev.parent = &video->device->dev;
1905 	input->evbit[0] = BIT(EV_KEY);
1906 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1907 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1908 	set_bit(KEY_VIDEO_PREV, input->keybit);
1909 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1910 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1911 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1912 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1913 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1914 
1915 	error = input_register_device(input);
1916 	if (error)
1917 		goto err_stop_dev;
1918 
1919 	mutex_lock(&video->device_list_lock);
1920 	list_for_each_entry(dev, &video->video_device_list, entry)
1921 		acpi_video_dev_add_notify_handler(dev);
1922 	mutex_unlock(&video->device_list_lock);
1923 
1924 	return 0;
1925 
1926 err_stop_dev:
1927 	acpi_video_bus_stop_devices(video);
1928 err_free_input:
1929 	input_free_device(input);
1930 	video->input = NULL;
1931 out:
1932 	return error;
1933 }
1934 
1935 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1936 {
1937 	if (dev->flags.notify) {
1938 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1939 					   acpi_video_device_notify);
1940 		dev->flags.notify = 0;
1941 	}
1942 }
1943 
1944 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1945 {
1946 	struct acpi_video_device *dev;
1947 
1948 	mutex_lock(&video->device_list_lock);
1949 	list_for_each_entry(dev, &video->video_device_list, entry)
1950 		acpi_video_dev_remove_notify_handler(dev);
1951 	mutex_unlock(&video->device_list_lock);
1952 
1953 	acpi_video_bus_stop_devices(video);
1954 	input_unregister_device(video->input);
1955 	video->input = NULL;
1956 }
1957 
1958 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1959 {
1960 	struct acpi_video_device *dev, *next;
1961 
1962 	mutex_lock(&video->device_list_lock);
1963 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1964 		list_del(&dev->entry);
1965 		kfree(dev);
1966 	}
1967 	mutex_unlock(&video->device_list_lock);
1968 
1969 	return 0;
1970 }
1971 
1972 static int instance;
1973 
1974 static int acpi_video_bus_add(struct acpi_device *device)
1975 {
1976 	struct acpi_video_bus *video;
1977 	bool auto_detect;
1978 	int error;
1979 	acpi_status status;
1980 
1981 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1982 				acpi_dev_parent(device)->handle, 1,
1983 				acpi_video_bus_match, NULL,
1984 				device, NULL);
1985 	if (status == AE_ALREADY_EXISTS) {
1986 		pr_info(FW_BUG
1987 			"Duplicate ACPI video bus devices for the"
1988 			" same VGA controller, please try module "
1989 			"parameter \"video.allow_duplicates=1\""
1990 			"if the current driver doesn't work.\n");
1991 		if (!allow_duplicates)
1992 			return -ENODEV;
1993 	}
1994 
1995 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1996 	if (!video)
1997 		return -ENOMEM;
1998 
1999 	/* a hack to fix the duplicate name "VID" problem on T61 */
2000 	if (!strcmp(device->pnp.bus_id, "VID")) {
2001 		if (instance)
2002 			device->pnp.bus_id[3] = '0' + instance;
2003 		instance++;
2004 	}
2005 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2006 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2007 		if (instance)
2008 			device->pnp.bus_id[3] = '0' + instance;
2009 		instance++;
2010 	}
2011 
2012 	video->device = device;
2013 	strscpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2014 	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2015 	device->driver_data = video;
2016 
2017 	acpi_video_bus_find_cap(video);
2018 	error = acpi_video_bus_check(video);
2019 	if (error)
2020 		goto err_free_video;
2021 
2022 	mutex_init(&video->device_list_lock);
2023 	INIT_LIST_HEAD(&video->video_device_list);
2024 
2025 	error = acpi_video_bus_get_devices(video, device);
2026 	if (error)
2027 		goto err_put_video;
2028 
2029 	/*
2030 	 * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
2031 	 * evaluated to have functional panel brightness control.
2032 	 */
2033 	acpi_device_fix_up_power_children(device);
2034 
2035 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2036 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2037 	       video->flags.multihead ? "yes" : "no",
2038 	       video->flags.rom ? "yes" : "no",
2039 	       video->flags.post ? "yes" : "no");
2040 	mutex_lock(&video_list_lock);
2041 	list_add_tail(&video->entry, &video_bus_head);
2042 	mutex_unlock(&video_list_lock);
2043 
2044 	/*
2045 	 * If backlight-type auto-detection is used then a native backlight may
2046 	 * show up later and this may change the result from video to native.
2047 	 * Therefor normally the userspace visible /sys/class/backlight device
2048 	 * gets registered separately by the GPU driver calling
2049 	 * acpi_video_register_backlight() when an internal panel is detected.
2050 	 * Register the backlight now when not using auto-detection, so that
2051 	 * when the kernel cmdline or DMI-quirks are used the backlight will
2052 	 * get registered even if acpi_video_register_backlight() is not called.
2053 	 */
2054 	acpi_video_run_bcl_for_osi(video);
2055 	if (__acpi_video_get_backlight_type(false, &auto_detect) == acpi_backlight_video &&
2056 	    !auto_detect)
2057 		acpi_video_bus_register_backlight(video);
2058 
2059 	error = acpi_video_bus_add_notify_handler(video);
2060 	if (error)
2061 		goto err_del;
2062 
2063 	error = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
2064 						acpi_video_bus_notify, device);
2065 	if (error)
2066 		goto err_remove;
2067 
2068 	return 0;
2069 
2070 err_remove:
2071 	acpi_video_bus_remove_notify_handler(video);
2072 err_del:
2073 	mutex_lock(&video_list_lock);
2074 	list_del(&video->entry);
2075 	mutex_unlock(&video_list_lock);
2076 	acpi_video_bus_unregister_backlight(video);
2077 err_put_video:
2078 	acpi_video_bus_put_devices(video);
2079 	kfree(video->attached_array);
2080 err_free_video:
2081 	kfree(video);
2082 	device->driver_data = NULL;
2083 
2084 	return error;
2085 }
2086 
2087 static void acpi_video_bus_remove(struct acpi_device *device)
2088 {
2089 	struct acpi_video_bus *video = NULL;
2090 
2091 
2092 	if (!device || !acpi_driver_data(device))
2093 		return;
2094 
2095 	video = acpi_driver_data(device);
2096 
2097 	acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
2098 				       acpi_video_bus_notify);
2099 
2100 	mutex_lock(&video_list_lock);
2101 	list_del(&video->entry);
2102 	mutex_unlock(&video_list_lock);
2103 
2104 	acpi_video_bus_remove_notify_handler(video);
2105 	acpi_video_bus_unregister_backlight(video);
2106 	acpi_video_bus_put_devices(video);
2107 
2108 	kfree(video->attached_array);
2109 	kfree(video);
2110 }
2111 
2112 static int __init is_i740(struct pci_dev *dev)
2113 {
2114 	if (dev->device == 0x00D1)
2115 		return 1;
2116 	if (dev->device == 0x7000)
2117 		return 1;
2118 	return 0;
2119 }
2120 
2121 static int __init intel_opregion_present(void)
2122 {
2123 	int opregion = 0;
2124 	struct pci_dev *dev = NULL;
2125 	u32 address;
2126 
2127 	for_each_pci_dev(dev) {
2128 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2129 			continue;
2130 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2131 			continue;
2132 		/* We don't want to poke around undefined i740 registers */
2133 		if (is_i740(dev))
2134 			continue;
2135 		pci_read_config_dword(dev, 0xfc, &address);
2136 		if (!address)
2137 			continue;
2138 		opregion = 1;
2139 	}
2140 	return opregion;
2141 }
2142 
2143 int acpi_video_register(void)
2144 {
2145 	int ret = 0;
2146 
2147 	mutex_lock(&register_count_mutex);
2148 	if (register_count) {
2149 		/*
2150 		 * if the function of acpi_video_register is already called,
2151 		 * don't register the acpi_video_bus again and return no error.
2152 		 */
2153 		goto leave;
2154 	}
2155 
2156 	dmi_check_system(video_dmi_table);
2157 
2158 	ret = acpi_bus_register_driver(&acpi_video_bus);
2159 	if (ret)
2160 		goto leave;
2161 
2162 	/*
2163 	 * When the acpi_video_bus is loaded successfully, increase
2164 	 * the counter reference.
2165 	 */
2166 	register_count = 1;
2167 
2168 leave:
2169 	mutex_unlock(&register_count_mutex);
2170 	return ret;
2171 }
2172 EXPORT_SYMBOL(acpi_video_register);
2173 
2174 void acpi_video_unregister(void)
2175 {
2176 	mutex_lock(&register_count_mutex);
2177 	if (register_count) {
2178 		acpi_bus_unregister_driver(&acpi_video_bus);
2179 		register_count = 0;
2180 		may_report_brightness_keys = false;
2181 	}
2182 	mutex_unlock(&register_count_mutex);
2183 }
2184 EXPORT_SYMBOL(acpi_video_unregister);
2185 
2186 void acpi_video_register_backlight(void)
2187 {
2188 	struct acpi_video_bus *video;
2189 
2190 	mutex_lock(&video_list_lock);
2191 	list_for_each_entry(video, &video_bus_head, entry)
2192 		acpi_video_bus_register_backlight(video);
2193 	mutex_unlock(&video_list_lock);
2194 }
2195 EXPORT_SYMBOL(acpi_video_register_backlight);
2196 
2197 bool acpi_video_handles_brightness_key_presses(void)
2198 {
2199 	return may_report_brightness_keys &&
2200 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2201 }
2202 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2203 
2204 /*
2205  * This is kind of nasty. Hardware using Intel chipsets may require
2206  * the video opregion code to be run first in order to initialise
2207  * state before any ACPI video calls are made. To handle this we defer
2208  * registration of the video class until the opregion code has run.
2209  */
2210 
2211 static int __init acpi_video_init(void)
2212 {
2213 	/*
2214 	 * Let the module load even if ACPI is disabled (e.g. due to
2215 	 * a broken BIOS) so that i915.ko can still be loaded on such
2216 	 * old systems without an AcpiOpRegion.
2217 	 *
2218 	 * acpi_video_register() will report -ENODEV later as well due
2219 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2220 	 */
2221 	if (acpi_disabled)
2222 		return 0;
2223 
2224 	if (intel_opregion_present())
2225 		return 0;
2226 
2227 	return acpi_video_register();
2228 }
2229 
2230 static void __exit acpi_video_exit(void)
2231 {
2232 	acpi_video_unregister();
2233 }
2234 
2235 module_init(acpi_video_init);
2236 module_exit(acpi_video_exit);
2237