2 * Copyright (C) 2008 SuSE Linux Products GmbH
3 * Thomas Renninger <trenn@suse.de>
5 * May be copied or modified under the terms of the GNU General Public License
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
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
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();
23 * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
24 * are available, video.ko should be used to handle the device.
26 * Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
27 * sony_acpi,... can take care about backlight brightness.
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.
36 #include <linux/export.h>
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39 #include <linux/pci.h>
41 #define PREFIX "ACPI: "
43 ACPI_MODULE_NAME("video");
44 #define _COMPONENT ACPI_VIDEO_COMPONENT
46 static long acpi_video_support
;
47 static bool acpi_video_caps_checked
;
50 acpi_backlight_cap_match(acpi_handle handle
, u32 level
, void *context
,
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 "
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
;
70 /* Returns true if the device is a video device which can be handled by
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
78 long acpi_is_video_device(struct acpi_device
*device
)
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
;
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
;
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
;
101 /* Only check for backlight functionality if one of the above hit. */
103 acpi_walk_namespace(ACPI_TYPE_DEVICE
, device
->handle
,
104 ACPI_UINT32_MAX
, acpi_backlight_cap_match
, NULL
,
109 EXPORT_SYMBOL(acpi_is_video_device
);
112 find_video(acpi_handle handle
, u32 lvl
, void *context
, void **rv
)
116 struct acpi_device
*acpi_dev
;
118 const struct acpi_device_id video_ids
[] = {
122 if (acpi_bus_get_device(handle
, &acpi_dev
))
125 if (!acpi_match_device_ids(acpi_dev
, video_ids
)) {
126 dev
= acpi_get_pci_dev(handle
);
130 *cap
|= acpi_is_video_device(acpi_dev
);
135 /* Force to use vendor driver when the ACPI device is known to be
137 static int video_detect_force_vendor(const struct dmi_system_id
*d
)
139 acpi_video_support
|= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
;
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().
151 .callback
= video_detect_force_vendor
,
154 DMI_MATCH(DMI_SYS_VENDOR
, "SAMSUNG ELECTRONICS CO., LTD."),
155 DMI_MATCH(DMI_PRODUCT_NAME
, "X360"),
156 DMI_MATCH(DMI_BOARD_NAME
, "X360"),
163 * Returns the video capabilities of a specific ACPI graphics device
165 * if NULL is passed as argument all ACPI devices are enumerated and
166 * all graphics capabilities of physically present devices are
167 * summarized and returned. This is cached and done only once.
169 long acpi_video_get_capabilities(acpi_handle graphics_handle
)
172 struct acpi_device
*tmp_dev
;
175 if (acpi_video_caps_checked
&& graphics_handle
== NULL
)
176 return acpi_video_support
;
178 if (!graphics_handle
) {
179 /* Only do the global walk through all graphics devices once */
180 acpi_walk_namespace(ACPI_TYPE_DEVICE
, ACPI_ROOT_OBJECT
,
181 ACPI_UINT32_MAX
, find_video
, NULL
,
183 /* There might be boot param flags set already... */
184 acpi_video_support
|= caps
;
185 acpi_video_caps_checked
= 1;
186 /* Add blacklists here. Be careful to use the right *DMI* bits
187 * to still be able to override logic via boot params, e.g.:
189 * if (dmi_name_in_vendors("XY")) {
190 * acpi_video_support |=
191 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
195 dmi_check_system(video_detect_dmi_table
);
197 status
= acpi_bus_get_device(graphics_handle
, &tmp_dev
);
198 if (ACPI_FAILURE(status
)) {
199 ACPI_EXCEPTION((AE_INFO
, status
, "Invalid device"));
202 acpi_walk_namespace(ACPI_TYPE_DEVICE
, graphics_handle
,
203 ACPI_UINT32_MAX
, find_video
, NULL
,
206 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "We have 0x%lX video support %s %s\n",
207 graphics_handle
? caps
: acpi_video_support
,
208 graphics_handle
? "on device " : "in general",
209 graphics_handle
? acpi_device_bid(tmp_dev
) : ""));
212 EXPORT_SYMBOL(acpi_video_get_capabilities
);
214 static void acpi_video_caps_check(void)
217 * We must check whether the ACPI graphics device is physically plugged
218 * in. Therefore this must be called after binding PCI and ACPI devices
220 if (!acpi_video_caps_checked
)
221 acpi_video_get_capabilities(NULL
);
224 /* Promote the vendor interface instead of the generic video module.
225 * This function allow DMI blacklists to be implemented by externals
226 * platform drivers instead of putting a big blacklist in video_detect.c
227 * After calling this function you will probably want to call
228 * acpi_video_unregister() to make sure the video module is not loaded
230 void acpi_video_dmi_promote_vendor(void)
232 acpi_video_caps_check();
233 acpi_video_support
|= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
;
235 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor
);
237 /* To be called when a driver who previously promoted the vendor
239 void acpi_video_dmi_demote_vendor(void)
241 acpi_video_caps_check();
242 acpi_video_support
&= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
;
244 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor
);
246 /* Returns true if video.ko can do backlight switching */
247 int acpi_video_backlight_support(void)
249 acpi_video_caps_check();
251 /* First check for boot param -> highest prio */
252 if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR
)
254 else if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO
)
257 /* Then check for DMI blacklist -> second highest prio */
258 if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
)
260 else if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_DMI_VIDEO
)
263 /* Then go the default way */
264 return acpi_video_support
& ACPI_VIDEO_BACKLIGHT
;
266 EXPORT_SYMBOL(acpi_video_backlight_support
);
269 * Use acpi_backlight=vendor/video to force that backlight switching
270 * is processed by vendor specific acpi drivers or video.ko driver.
272 static int __init
acpi_backlight(char *str
)
274 if (str
== NULL
|| *str
== '\0')
277 if (!strcmp("vendor", str
))
278 acpi_video_support
|=
279 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR
;
280 if (!strcmp("video", str
))
281 acpi_video_support
|=
282 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO
;
286 __setup("acpi_backlight=", acpi_backlight
);