ACPI: video: Loosen strictness of video bus detection code
[linux-3.10.git] / 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  * assinged
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 (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 #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 "ACPI brightness "
63                                         "control misses _BQC function\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         /* Does 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         /* Does 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         /* Does 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,
105                                     &video_caps, NULL);
106
107         return video_caps;
108 }
109 EXPORT_SYMBOL(acpi_is_video_device);
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 /*
136  * Returns the video capabilities of a specific ACPI graphics device
137  *
138  * if NULL is passed as argument all ACPI devices are enumerated and
139  * all graphics capabilities of physically present devices are
140  * summerized and returned. This is cached and done only once.
141  */
142 long acpi_video_get_capabilities(acpi_handle graphics_handle)
143 {
144         long caps = 0;
145         struct acpi_device *tmp_dev;
146         acpi_status status;
147
148         if (acpi_video_caps_checked && graphics_handle == NULL)
149                 return acpi_video_support;
150
151         if (!graphics_handle) {
152                 /* Only do the global walk through all graphics devices once */
153                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
154                                     ACPI_UINT32_MAX, find_video,
155                                     &caps, NULL);
156                 /* There might be boot param flags set already... */
157                 acpi_video_support |= caps;
158                 acpi_video_caps_checked = 1;
159                 /* Add blacklists here. Be careful to use the right *DMI* bits
160                  * to still be able to override logic via boot params, e.g.:
161                  *
162                  *   if (dmi_name_in_vendors("XY")) {
163                  *      acpi_video_support |=
164                  *              ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
165                  *      acpi_video_support |=
166                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
167                  *}
168                  */
169         } else {
170                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
171                 if (ACPI_FAILURE(status)) {
172                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
173                         return 0;
174                 }
175                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
176                                     ACPI_UINT32_MAX, find_video,
177                                     &caps, NULL);
178         }
179         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
180                           graphics_handle ? caps : acpi_video_support,
181                           graphics_handle ? "on device " : "in general",
182                           graphics_handle ? acpi_device_bid(tmp_dev) : ""));
183         return caps;
184 }
185 EXPORT_SYMBOL(acpi_video_get_capabilities);
186
187 /* Returns true if video.ko can do backlight switching */
188 int acpi_video_backlight_support(void)
189 {
190         /*
191          * We must check whether the ACPI graphics device is physically plugged
192          * in. Therefore this must be called after binding PCI and ACPI devices
193          */
194         if (!acpi_video_caps_checked)
195                 acpi_video_get_capabilities(NULL);
196
197         /* First check for boot param -> highest prio */
198         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
199                 return 0;
200         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
201                 return 1;
202
203         /* Then check for DMI blacklist -> second highest prio */
204         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
205                 return 0;
206         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
207                 return 1;
208
209         /* Then go the default way */
210         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
211 }
212 EXPORT_SYMBOL(acpi_video_backlight_support);
213
214 /*
215  * Returns true if video.ko can do display output switching.
216  * This does not work well/at all with binary graphics drivers
217  * which disable system io ranges and do it on their own.
218  */
219 int acpi_video_display_switch_support(void)
220 {
221         if (!acpi_video_caps_checked)
222                 acpi_video_get_capabilities(NULL);
223
224         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR)
225                 return 0;
226         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO)
227                 return 1;
228
229         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR)
230                 return 0;
231         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO)
232                 return 1;
233
234         return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING;
235 }
236 EXPORT_SYMBOL(acpi_video_display_switch_support);
237
238 /*
239  * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
240  * To force that backlight or display output switching is processed by vendor
241  * specific acpi drivers or video.ko driver.
242  */
243 static int __init acpi_backlight(char *str)
244 {
245         if (str == NULL || *str == '\0')
246                 return 1;
247         else {
248                 if (!strcmp("vendor", str))
249                         acpi_video_support |=
250                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
251                 if (!strcmp("video", str))
252                         acpi_video_support |=
253                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
254         }
255         return 1;
256 }
257 __setup("acpi_backlight=", acpi_backlight);
258
259 static int __init acpi_display_output(char *str)
260 {
261         if (str == NULL || *str == '\0')
262                 return 1;
263         else {
264                 if (!strcmp("vendor", str))
265                         acpi_video_support |=
266                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR;
267                 if (!strcmp("video", str))
268                         acpi_video_support |=
269                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
270         }
271         return 1;
272 }
273 __setup("acpi_display_output=", acpi_display_output);