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>
43 #define PREFIX "ACPI: "
45 ACPI_MODULE_NAME("video");
46 #define _COMPONENT ACPI_VIDEO_COMPONENT
48 static long acpi_video_support;
49 static bool acpi_video_caps_checked;
52 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
58 if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
59 ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
60 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
62 *cap |= ACPI_VIDEO_BACKLIGHT;
63 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
64 printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
65 "cannot determine initial brightness\n");
66 /* We have backlight support, no need to scan further */
67 return AE_CTRL_TERMINATE;
72 /* Returns true if the ACPI object is a video device which can be
73 * handled by video.ko.
74 * The device will get a Linux specific CID added in scan.c to
75 * identify the device as an ACPI graphics device
76 * Be aware that the graphics device may not be physically present
77 * Use acpi_video_get_capabilities() to detect general ACPI video
78 * capabilities of present cards
80 long acpi_is_video_device(acpi_handle handle)
85 /* Is this device able to support video switching ? */
86 if (ACPI_SUCCESS(acpi_get_handle(handle, "_DOD", &h_dummy)) ||
87 ACPI_SUCCESS(acpi_get_handle(handle, "_DOS", &h_dummy)))
88 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
90 /* Is this device able to retrieve a video ROM ? */
91 if (ACPI_SUCCESS(acpi_get_handle(handle, "_ROM", &h_dummy)))
92 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
94 /* Is this device able to configure which video head to be POSTed ? */
95 if (ACPI_SUCCESS(acpi_get_handle(handle, "_VPO", &h_dummy)) &&
96 ACPI_SUCCESS(acpi_get_handle(handle, "_GPD", &h_dummy)) &&
97 ACPI_SUCCESS(acpi_get_handle(handle, "_SPD", &h_dummy)))
98 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
100 /* Only check for backlight functionality if one of the above hit. */
102 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
103 ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
108 EXPORT_SYMBOL(acpi_is_video_device);
111 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
115 struct acpi_device *acpi_dev;
117 const struct acpi_device_id video_ids[] = {
121 if (acpi_bus_get_device(handle, &acpi_dev))
124 if (!acpi_match_device_ids(acpi_dev, video_ids)) {
125 dev = acpi_get_pci_dev(handle);
129 *cap |= acpi_is_video_device(handle);
134 /* Force to use vendor driver when the ACPI device is known to be
136 static int video_detect_force_vendor(const struct dmi_system_id *d)
138 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
142 static struct dmi_system_id video_detect_dmi_table[] = {
143 /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
144 * ACPI backlight device is used. This flag will definitively break
145 * the backlight interface (even the vendor interface) untill next
146 * reboot. It's why we should prevent video.ko from being used here
147 * and we can't rely on a later call to acpi_video_unregister().
150 .callback = video_detect_force_vendor,
153 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
154 DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
155 DMI_MATCH(DMI_BOARD_NAME, "X360"),
159 .callback = video_detect_force_vendor,
160 .ident = "Asus UL30VT",
162 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
163 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
167 .callback = video_detect_force_vendor,
168 .ident = "Asus UL30A",
170 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
171 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
178 * Returns the video capabilities of a specific ACPI graphics device
180 * if NULL is passed as argument all ACPI devices are enumerated and
181 * all graphics capabilities of physically present devices are
182 * summarized and returned. This is cached and done only once.
184 long acpi_video_get_capabilities(acpi_handle graphics_handle)
187 struct acpi_device *tmp_dev;
190 if (acpi_video_caps_checked && graphics_handle == NULL)
191 return acpi_video_support;
193 if (!graphics_handle) {
194 /* Only do the global walk through all graphics devices once */
195 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
196 ACPI_UINT32_MAX, find_video, NULL,
198 /* There might be boot param flags set already... */
199 acpi_video_support |= caps;
200 acpi_video_caps_checked = 1;
201 /* Add blacklists here. Be careful to use the right *DMI* bits
202 * to still be able to override logic via boot params, e.g.:
204 * if (dmi_name_in_vendors("XY")) {
205 * acpi_video_support |=
206 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
210 dmi_check_system(video_detect_dmi_table);
212 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
213 if (ACPI_FAILURE(status)) {
214 ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
217 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
218 ACPI_UINT32_MAX, find_video, NULL,
221 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
222 graphics_handle ? caps : acpi_video_support,
223 graphics_handle ? "on device " : "in general",
224 graphics_handle ? acpi_device_bid(tmp_dev) : ""));
227 EXPORT_SYMBOL(acpi_video_get_capabilities);
229 static void acpi_video_caps_check(void)
232 * We must check whether the ACPI graphics device is physically plugged
233 * in. Therefore this must be called after binding PCI and ACPI devices
235 if (!acpi_video_caps_checked)
236 acpi_video_get_capabilities(NULL);
239 bool acpi_video_backlight_quirks(void)
241 return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
243 EXPORT_SYMBOL(acpi_video_backlight_quirks);
245 /* Promote the vendor interface instead of the generic video module.
246 * This function allow DMI blacklists to be implemented by externals
247 * platform drivers instead of putting a big blacklist in video_detect.c
248 * After calling this function you will probably want to call
249 * acpi_video_unregister() to make sure the video module is not loaded
251 void acpi_video_dmi_promote_vendor(void)
253 acpi_video_caps_check();
254 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
256 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
258 /* To be called when a driver who previously promoted the vendor
260 void acpi_video_dmi_demote_vendor(void)
262 acpi_video_caps_check();
263 acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
265 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
267 /* Returns true if video.ko can do backlight switching */
268 int acpi_video_backlight_support(void)
270 acpi_video_caps_check();
272 /* First check for boot param -> highest prio */
273 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
275 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
278 /* Then check for DMI blacklist -> second highest prio */
279 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
281 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
284 /* Then go the default way */
285 return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
287 EXPORT_SYMBOL(acpi_video_backlight_support);
290 * Use acpi_backlight=vendor/video to force that backlight switching
291 * is processed by vendor specific acpi drivers or video.ko driver.
293 static int __init acpi_backlight(char *str)
295 if (str == NULL || *str == '\0')
298 if (!strcmp("vendor", str))
299 acpi_video_support |=
300 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
301 if (!strcmp("video", str))
302 acpi_video_support |=
303 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
307 __setup("acpi_backlight=", acpi_backlight);