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Linux/drivers/acpi/video_detect.c

  1 /*
  2  *  Copyright (C) 2008       SuSE Linux Products GmbH
  3  *                           Thomas Renninger <trenn@suse.de>
  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 #include "internal.h"
 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 **return_value)
 52 {
 53         long *cap = context;
 54 
 55         if (acpi_has_method(handle, "_BCM") &&
 56             acpi_has_method(handle, "_BCL")) {
 57                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
 58                                   "support\n"));
 59                 *cap |= ACPI_VIDEO_BACKLIGHT;
 60                 if (!acpi_has_method(handle, "_BQC"))
 61                         printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
 62                                 "cannot determine initial brightness\n");
 63                 /* We have backlight support, no need to scan further */
 64                 return AE_CTRL_TERMINATE;
 65         }
 66         return 0;
 67 }
 68 
 69 /* Returns true if the ACPI object is a video device which can be
 70  * handled by video.ko.
 71  * The device will get a Linux specific CID added in scan.c to
 72  * identify the device as an ACPI graphics device
 73  * Be aware that the graphics device may not be physically present
 74  * Use acpi_video_get_capabilities() to detect general ACPI video
 75  * capabilities of present cards
 76  */
 77 long acpi_is_video_device(acpi_handle handle)
 78 {
 79         long video_caps = 0;
 80 
 81         /* Is this device able to support video switching ? */
 82         if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS"))
 83                 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
 84 
 85         /* Is this device able to retrieve a video ROM ? */
 86         if (acpi_has_method(handle, "_ROM"))
 87                 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
 88 
 89         /* Is this device able to configure which video head to be POSTed ? */
 90         if (acpi_has_method(handle, "_VPO") &&
 91             acpi_has_method(handle, "_GPD") &&
 92             acpi_has_method(handle, "_SPD"))
 93                 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
 94 
 95         /* Only check for backlight functionality if one of the above hit. */
 96         if (video_caps)
 97                 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
 98                                     ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
 99                                     &video_caps, NULL);
100 
101         return video_caps;
102 }
103 EXPORT_SYMBOL(acpi_is_video_device);
104 
105 static acpi_status
106 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
107 {
108         long *cap = context;
109         struct pci_dev *dev;
110         struct acpi_device *acpi_dev;
111 
112         const struct acpi_device_id video_ids[] = {
113                 {ACPI_VIDEO_HID, 0},
114                 {"", 0},
115         };
116         if (acpi_bus_get_device(handle, &acpi_dev))
117                 return AE_OK;
118 
119         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
120                 dev = acpi_get_pci_dev(handle);
121                 if (!dev)
122                         return AE_OK;
123                 pci_dev_put(dev);
124                 *cap |= acpi_is_video_device(handle);
125         }
126         return AE_OK;
127 }
128 
129 /* Force to use vendor driver when the ACPI device is known to be
130  * buggy */
131 static int video_detect_force_vendor(const struct dmi_system_id *d)
132 {
133         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
134         return 0;
135 }
136 
137 static struct dmi_system_id video_detect_dmi_table[] = {
138         /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
139          * ACPI backlight device is used. This flag will definitively break
140          * the backlight interface (even the vendor interface) untill next
141          * reboot. It's why we should prevent video.ko from being used here
142          * and we can't rely on a later call to acpi_video_unregister().
143          */
144         {
145          .callback = video_detect_force_vendor,
146          .ident = "X360",
147          .matches = {
148                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
149                 DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
150                 DMI_MATCH(DMI_BOARD_NAME, "X360"),
151                 },
152         },
153         {
154         .callback = video_detect_force_vendor,
155         .ident = "Asus UL30VT",
156         .matches = {
157                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
158                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
159                 },
160         },
161         {
162         .callback = video_detect_force_vendor,
163         .ident = "Asus UL30A",
164         .matches = {
165                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
166                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
167                 },
168         },
169         {
170         .callback = video_detect_force_vendor,
171         .ident = "Dell Inspiron 5737",
172         .matches = {
173                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
174                 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 5737"),
175                 },
176         },
177         { },
178 };
179 
180 /*
181  * Returns the video capabilities of a specific ACPI graphics device
182  *
183  * if NULL is passed as argument all ACPI devices are enumerated and
184  * all graphics capabilities of physically present devices are
185  * summarized and returned. This is cached and done only once.
186  */
187 long acpi_video_get_capabilities(acpi_handle graphics_handle)
188 {
189         long caps = 0;
190         struct acpi_device *tmp_dev;
191         acpi_status status;
192 
193         if (acpi_video_caps_checked && graphics_handle == NULL)
194                 return acpi_video_support;
195 
196         if (!graphics_handle) {
197                 /* Only do the global walk through all graphics devices once */
198                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
199                                     ACPI_UINT32_MAX, find_video, NULL,
200                                     &caps, NULL);
201                 /* There might be boot param flags set already... */
202                 acpi_video_support |= caps;
203                 acpi_video_caps_checked = 1;
204                 /* Add blacklists here. Be careful to use the right *DMI* bits
205                  * to still be able to override logic via boot params, e.g.:
206                  *
207                  *   if (dmi_name_in_vendors("XY")) {
208                  *      acpi_video_support |=
209                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
210                  *}
211                  */
212 
213                 dmi_check_system(video_detect_dmi_table);
214         } else {
215                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
216                 if (ACPI_FAILURE(status)) {
217                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
218                         return 0;
219                 }
220                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
221                                     ACPI_UINT32_MAX, find_video, NULL,
222                                     &caps, NULL);
223         }
224         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
225                           graphics_handle ? caps : acpi_video_support,
226                           graphics_handle ? "on device " : "in general",
227                           graphics_handle ? acpi_device_bid(tmp_dev) : ""));
228         return caps;
229 }
230 EXPORT_SYMBOL(acpi_video_get_capabilities);
231 
232 static void acpi_video_caps_check(void)
233 {
234         /*
235          * We must check whether the ACPI graphics device is physically plugged
236          * in. Therefore this must be called after binding PCI and ACPI devices
237          */
238         if (!acpi_video_caps_checked)
239                 acpi_video_get_capabilities(NULL);
240 }
241 
242 bool acpi_osi_is_win8(void)
243 {
244         return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
245 }
246 EXPORT_SYMBOL(acpi_osi_is_win8);
247 
248 /* Promote the vendor interface instead of the generic video module.
249  * This function allow DMI blacklists to be implemented by externals
250  * platform drivers instead of putting a big blacklist in video_detect.c
251  * After calling this function you will probably want to call
252  * acpi_video_unregister() to make sure the video module is not loaded
253  */
254 void acpi_video_dmi_promote_vendor(void)
255 {
256         acpi_video_caps_check();
257         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
258 }
259 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
260 
261 /* To be called when a driver who previously promoted the vendor
262  * interface */
263 void acpi_video_dmi_demote_vendor(void)
264 {
265         acpi_video_caps_check();
266         acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
267 }
268 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
269 
270 /* Returns true if video.ko can do backlight switching */
271 int acpi_video_backlight_support(void)
272 {
273         acpi_video_caps_check();
274 
275         /* First check for boot param -> highest prio */
276         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
277                 return 0;
278         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
279                 return 1;
280 
281         /* Then check for DMI blacklist -> second highest prio */
282         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
283                 return 0;
284         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
285                 return 1;
286 
287         /* Then go the default way */
288         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
289 }
290 EXPORT_SYMBOL(acpi_video_backlight_support);
291 
292 /*
293  * Use acpi_backlight=vendor/video to force that backlight switching
294  * is processed by vendor specific acpi drivers or video.ko driver.
295  */
296 static int __init acpi_backlight(char *str)
297 {
298         if (str == NULL || *str == '\0')
299                 return 1;
300         else {
301                 if (!strcmp("vendor", str))
302                         acpi_video_support |=
303                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
304                 if (!strcmp("video", str))
305                         acpi_video_support |=
306                                 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
307         }
308         return 1;
309 }
310 __setup("acpi_backlight=", acpi_backlight);
311 

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