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_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
  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  */
  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
 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  */
 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 */
 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  */
 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  */
 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
 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);