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 * assinged
11 *
12 * After PCI devices are glued with ACPI devices
13 * acpi_get_physical_pci_device() 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 (or display output) 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_acpi,
27 * sony_acpi,... can take care about backlight brightness and display output
28 * switching.
29 *
30 * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
31 * this file will not be compiled, acpi_video_get_capabilities() and
32 * acpi_video_backlight_support() will always return 0 and vendor specific
33 * drivers always can handle backlight.
34 *
35 */
36
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39
40 ACPI_MODULE_NAME("video");
41 #define _COMPONENT ACPI_VIDEO_COMPONENT
42
43 static long acpi_video_support;
44 static bool acpi_video_caps_checked;
45
46 static acpi_status
acpi_backlight_cap_match(acpi_handle handle,u32 level,void * context,void ** retyurn_value)47 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
48 void **retyurn_value)
49 {
50 long *cap = context;
51 acpi_handle h_dummy;
52
53 if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
54 ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
55 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
56 "support\n"));
57 *cap |= ACPI_VIDEO_BACKLIGHT;
58 /* We have backlight support, no need to scan further */
59 return AE_CTRL_TERMINATE;
60 }
61 return 0;
62 }
63
64 /* Returns true if the device is a video device which can be handled by
65 * video.ko.
66 * The device will get a Linux specific CID added in scan.c to
67 * identify the device as an ACPI graphics device
68 * Be aware that the graphics device may not be physically present
69 * Use acpi_video_get_capabilities() to detect general ACPI video
70 * capabilities of present cards
71 */
acpi_is_video_device(struct acpi_device * device)72 long acpi_is_video_device(struct acpi_device *device)
73 {
74 acpi_handle h_dummy;
75 long video_caps = 0;
76
77 if (!device)
78 return 0;
79
80 /* Does this device able to support video switching ? */
81 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) &&
82 ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
83 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
84
85 /* Does this device able to retrieve a video ROM ? */
86 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
87 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
88
89 /* Does this device able to configure which video head to be POSTed ? */
90 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
91 ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
92 ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
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, device->handle,
98 ACPI_UINT32_MAX, acpi_backlight_cap_match,
99 &video_caps, NULL);
100
101 return video_caps;
102 }
103 EXPORT_SYMBOL(acpi_is_video_device);
104
105 static acpi_status
find_video(acpi_handle handle,u32 lvl,void * context,void ** rv)106 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
107 {
108 long *cap = context;
109 struct device *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_physical_pci_device(handle);
121 if (!dev)
122 return AE_OK;
123 put_device(dev);
124 *cap |= acpi_is_video_device(acpi_dev);
125 }
126 return AE_OK;
127 }
128
129 /*
130 * Returns the video capabilities of a specific ACPI graphics device
131 *
132 * if NULL is passed as argument all ACPI devices are enumerated and
133 * all graphics capabilities of physically present devices are
134 * summerized and returned. This is cached and done only once.
135 */
acpi_video_get_capabilities(acpi_handle graphics_handle)136 long acpi_video_get_capabilities(acpi_handle graphics_handle)
137 {
138 long caps = 0;
139 struct acpi_device *tmp_dev;
140 acpi_status status;
141
142 if (acpi_video_caps_checked && graphics_handle == NULL)
143 return acpi_video_support;
144
145 if (!graphics_handle) {
146 /* Only do the global walk through all graphics devices once */
147 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
148 ACPI_UINT32_MAX, find_video,
149 &caps, NULL);
150 /* There might be boot param flags set already... */
151 acpi_video_support |= caps;
152 acpi_video_caps_checked = 1;
153 /* Add blacklists here. Be careful to use the right *DMI* bits
154 * to still be able to override logic via boot params, e.g.:
155 *
156 * if (dmi_name_in_vendors("XY")) {
157 * acpi_video_support |=
158 * ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
159 * acpi_video_support |=
160 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
161 *}
162 */
163 } else {
164 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
165 if (ACPI_FAILURE(status)) {
166 ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
167 return 0;
168 }
169 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
170 ACPI_UINT32_MAX, find_video,
171 &caps, NULL);
172 }
173 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
174 graphics_handle ? caps : acpi_video_support,
175 graphics_handle ? "on device " : "in general",
176 graphics_handle ? acpi_device_bid(tmp_dev) : ""));
177 return caps;
178 }
179 EXPORT_SYMBOL(acpi_video_get_capabilities);
180
181 /* Returns true if video.ko can do backlight switching */
acpi_video_backlight_support(void)182 int acpi_video_backlight_support(void)
183 {
184 /*
185 * We must check whether the ACPI graphics device is physically plugged
186 * in. Therefore this must be called after binding PCI and ACPI devices
187 */
188 if (!acpi_video_caps_checked)
189 acpi_video_get_capabilities(NULL);
190
191 /* First check for boot param -> highest prio */
192 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
193 return 0;
194 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
195 return 1;
196
197 /* Then check for DMI blacklist -> second highest prio */
198 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
199 return 0;
200 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
201 return 1;
202
203 /* Then go the default way */
204 return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
205 }
206 EXPORT_SYMBOL(acpi_video_backlight_support);
207
208 /*
209 * Returns true if video.ko can do display output switching.
210 * This does not work well/at all with binary graphics drivers
211 * which disable system io ranges and do it on their own.
212 */
acpi_video_display_switch_support(void)213 int acpi_video_display_switch_support(void)
214 {
215 if (!acpi_video_caps_checked)
216 acpi_video_get_capabilities(NULL);
217
218 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR)
219 return 0;
220 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO)
221 return 1;
222
223 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR)
224 return 0;
225 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO)
226 return 1;
227
228 return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING;
229 }
230 EXPORT_SYMBOL(acpi_video_display_switch_support);
231
232 /*
233 * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
234 * To force that backlight or display output switching is processed by vendor
235 * specific acpi drivers or video.ko driver.
236 */
acpi_backlight(char * str)237 static int __init acpi_backlight(char *str)
238 {
239 if (str == NULL || *str == '\0')
240 return 1;
241 else {
242 if (!strcmp("vendor", str))
243 acpi_video_support |=
244 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
245 if (!strcmp("video", str))
246 acpi_video_support |=
247 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
248 }
249 return 1;
250 }
251 __setup("acpi_backlight=", acpi_backlight);
252
acpi_display_output(char * str)253 static int __init acpi_display_output(char *str)
254 {
255 if (str == NULL || *str == '\0')
256 return 1;
257 else {
258 if (!strcmp("vendor", str))
259 acpi_video_support |=
260 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR;
261 if (!strcmp("video", str))
262 acpi_video_support |=
263 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
264 }
265 return 1;
266 }
267 __setup("acpi_display_output=", acpi_display_output);
268