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video_detect.c
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1 /*
2  * Copyright (C) 2008 SuSE Linux Products GmbH
3  * Thomas Renninger <[email protected]>
4  *
5  * May be copied or modified under the terms of the GNU General Public License
6  *
7  * video_detect.c:
8  * Provides acpi_is_video_device() for early scanning of ACPI devices in scan.c
9  * There a Linux specific (Spec does not provide a HID for video devices) is
10  * assigned
11  *
12  * After PCI devices are glued with ACPI devices
13  * acpi_get_pci_dev() can be called to identify ACPI graphics
14  * devices for which a real graphics card is plugged in
15  *
16  * Now acpi_video_get_capabilities() can be called to check which
17  * capabilities the graphics cards plugged in support. The check for general
18  * video capabilities will be triggered by the first caller of
19  * acpi_video_get_capabilities(NULL); which will happen when the first
20  * backlight switching supporting driver calls:
21  * acpi_video_backlight_support();
22  *
23  * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
24  * are available, video.ko should be used to handle the device.
25  *
26  * Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
27  * sony_acpi,... can take care about backlight brightness.
28  *
29  * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
30  * this file will not be compiled, acpi_video_get_capabilities() and
31  * acpi_video_backlight_support() will always return 0 and vendor specific
32  * drivers always can handle backlight.
33  *
34  */
35 
36 #include <linux/export.h>
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39 #include <linux/pci.h>
40 
41 #define PREFIX "ACPI: "
42 
43 ACPI_MODULE_NAME("video");
44 #define _COMPONENT ACPI_VIDEO_COMPONENT
45 
46 static long acpi_video_support;
47 static bool acpi_video_caps_checked;
48 
49 static acpi_status
50 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
51  void **retyurn_value)
52 {
53  long *cap = context;
54  acpi_handle h_dummy;
55 
56  if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
57  ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
58  ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
59  "support\n"));
60  *cap |= ACPI_VIDEO_BACKLIGHT;
61  if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
62  printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
63  "cannot determine initial brightness\n");
64  /* We have backlight support, no need to scan further */
65  return AE_CTRL_TERMINATE;
66  }
67  return 0;
68 }
69 
70 /* Returns true if the device is a video device which can be handled by
71  * video.ko.
72  * The device will get a Linux specific CID added in scan.c to
73  * identify the device as an ACPI graphics device
74  * Be aware that the graphics device may not be physically present
75  * Use acpi_video_get_capabilities() to detect general ACPI video
76  * capabilities of present cards
77  */
78 long acpi_is_video_device(struct acpi_device *device)
79 {
80  acpi_handle h_dummy;
81  long video_caps = 0;
82 
83  if (!device)
84  return 0;
85 
86  /* Is this device able to support video switching ? */
87  if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) ||
88  ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
89  video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
90 
91  /* Is this device able to retrieve a video ROM ? */
92  if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
93  video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
94 
95  /* Is this device able to configure which video head to be POSTed ? */
96  if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
97  ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
98  ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
99  video_caps |= ACPI_VIDEO_DEVICE_POSTING;
100 
101  /* Only check for backlight functionality if one of the above hit. */
102  if (video_caps)
103  acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle,
104  ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
105  &video_caps, NULL);
106 
107  return video_caps;
108 }
110 
111 static acpi_status
112 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
113 {
114  long *cap = context;
115  struct pci_dev *dev;
116  struct acpi_device *acpi_dev;
117 
118  const struct acpi_device_id video_ids[] = {
119  {ACPI_VIDEO_HID, 0},
120  {"", 0},
121  };
122  if (acpi_bus_get_device(handle, &acpi_dev))
123  return AE_OK;
124 
125  if (!acpi_match_device_ids(acpi_dev, video_ids)) {
126  dev = acpi_get_pci_dev(handle);
127  if (!dev)
128  return AE_OK;
129  pci_dev_put(dev);
130  *cap |= acpi_is_video_device(acpi_dev);
131  }
132  return AE_OK;
133 }
134 
135 /* Force to use vendor driver when the ACPI device is known to be
136  * buggy */
137 static int video_detect_force_vendor(const struct dmi_system_id *d)
138 {
139  acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
140  return 0;
141 }
142 
143 static struct dmi_system_id video_detect_dmi_table[] = {
144  /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
145  * ACPI backlight device is used. This flag will definitively break
146  * the backlight interface (even the vendor interface) untill next
147  * reboot. It's why we should prevent video.ko from being used here
148  * and we can't rely on a later call to acpi_video_unregister().
149  */
150  {
151  .callback = video_detect_force_vendor,
152  .ident = "X360",
153  .matches = {
154  DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
155  DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
156  DMI_MATCH(DMI_BOARD_NAME, "X360"),
157  },
158  },
159  {
160  .callback = video_detect_force_vendor,
161  .ident = "Asus UL30VT",
162  .matches = {
163  DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
164  DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
165  },
166  },
167  { },
168 };
169 
170 /*
171  * Returns the video capabilities of a specific ACPI graphics device
172  *
173  * if NULL is passed as argument all ACPI devices are enumerated and
174  * all graphics capabilities of physically present devices are
175  * summarized and returned. This is cached and done only once.
176  */
178 {
179  long caps = 0;
180  struct acpi_device *tmp_dev;
182 
183  if (acpi_video_caps_checked && graphics_handle == NULL)
184  return acpi_video_support;
185 
186  if (!graphics_handle) {
187  /* Only do the global walk through all graphics devices once */
189  ACPI_UINT32_MAX, find_video, NULL,
190  &caps, NULL);
191  /* There might be boot param flags set already... */
192  acpi_video_support |= caps;
193  acpi_video_caps_checked = 1;
194  /* Add blacklists here. Be careful to use the right *DMI* bits
195  * to still be able to override logic via boot params, e.g.:
196  *
197  * if (dmi_name_in_vendors("XY")) {
198  * acpi_video_support |=
199  * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
200  *}
201  */
202 
203  dmi_check_system(video_detect_dmi_table);
204  } else {
205  status = acpi_bus_get_device(graphics_handle, &tmp_dev);
206  if (ACPI_FAILURE(status)) {
207  ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
208  return 0;
209  }
210  acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
211  ACPI_UINT32_MAX, find_video, NULL,
212  &caps, NULL);
213  }
214  ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
215  graphics_handle ? caps : acpi_video_support,
216  graphics_handle ? "on device " : "in general",
217  graphics_handle ? acpi_device_bid(tmp_dev) : ""));
218  return caps;
219 }
221 
222 static void acpi_video_caps_check(void)
223 {
224  /*
225  * We must check whether the ACPI graphics device is physically plugged
226  * in. Therefore this must be called after binding PCI and ACPI devices
227  */
228  if (!acpi_video_caps_checked)
230 }
231 
232 /* Promote the vendor interface instead of the generic video module.
233  * This function allow DMI blacklists to be implemented by externals
234  * platform drivers instead of putting a big blacklist in video_detect.c
235  * After calling this function you will probably want to call
236  * acpi_video_unregister() to make sure the video module is not loaded
237  */
239 {
240  acpi_video_caps_check();
241  acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
242 }
244 
245 /* To be called when a driver who previously promoted the vendor
246  * interface */
248 {
249  acpi_video_caps_check();
250  acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
251 }
253 
254 /* Returns true if video.ko can do backlight switching */
256 {
257  acpi_video_caps_check();
258 
259  /* First check for boot param -> highest prio */
260  if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
261  return 0;
262  else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
263  return 1;
264 
265  /* Then check for DMI blacklist -> second highest prio */
266  if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
267  return 0;
268  else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
269  return 1;
270 
271  /* Then go the default way */
272  return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
273 }
275 
276 /*
277  * Use acpi_backlight=vendor/video to force that backlight switching
278  * is processed by vendor specific acpi drivers or video.ko driver.
279  */
280 static int __init acpi_backlight(char *str)
281 {
282  if (str == NULL || *str == '\0')
283  return 1;
284  else {
285  if (!strcmp("vendor", str))
286  acpi_video_support |=
287  ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
288  if (!strcmp("video", str))
289  acpi_video_support |=
290  ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
291  }
292  return 1;
293 }
294 __setup("acpi_backlight=", acpi_backlight);