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  * assigned
  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 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-laptop,
  27  * sony_acpi,... can take care about backlight brightness.
  28  *
  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.
  33  *
  34  */
  35
  36 #include <linux/export.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/pci.h>
  40
  41 #include "internal.h"
  42
  43 #define PREFIX "ACPI: "
  44
  45 ACPI_MODULE_NAME("video");
  46 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  47
  48 static long acpi_video_support;
  49 static bool acpi_video_caps_checked;
  50
  51 static acpi_status
  52 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
  53                           void **retyurn_value)
  54 {
  55         long *cap = context;
  56         acpi_handle h_dummy;
  57
  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 "
  61                                   "support\n"));
  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;
  68         }
  69         return 0;
  70 }
  71
  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
  79  */
  80 long acpi_is_video_device(acpi_handle handle)
  81 {
  82         acpi_handle h_dummy;
  83         long video_caps = 0;
  84
  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;
  89
  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;
  93
  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;
  99
 100         /* Only check for backlight functionality if one of the above hit. */
 101         if (video_caps)
 102                 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
 103                                     ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
 104                                     &video_caps, NULL);
 105
 106         return video_caps;
 107 }
 108 EXPORT_SYMBOL(acpi_is_video_device);
 109
 110 static acpi_status
 111 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 112 {
 113         long *cap = context;
 114         struct pci_dev *dev;
 115         struct acpi_device *acpi_dev;
 116
 117         const struct acpi_device_id video_ids[] = {
 118                 {ACPI_VIDEO_HID, 0},
 119                 {"", 0},
 120         };
 121         if (acpi_bus_get_device(handle, &acpi_dev))
 122                 return AE_OK;
 123
 124         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
 125                 dev = acpi_get_pci_dev(handle);
 126                 if (!dev)
 127                         return AE_OK;
 128                 pci_dev_put(dev);
 129                 *cap |= acpi_is_video_device(handle);
 130         }
 131         return AE_OK;
 132 }
 133
 134 /* Force to use vendor driver when the ACPI device is known to be
 135  * buggy */
 136 static int video_detect_force_vendor(const struct dmi_system_id *d)
 137 {
 138         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 139         return 0;
 140 }
 141
 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().
 148          */
 149         {
 150          .callback = video_detect_force_vendor,
 151          .ident = "X360",
 152          .matches = {
 153                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 154                 DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
 155                 DMI_MATCH(DMI_BOARD_NAME, "X360"),
 156                 },
 157         },
 158         {
 159         .callback = video_detect_force_vendor,
 160         .ident = "Asus UL30VT",
 161         .matches = {
 162                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 163                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
 164                 },
 165         },
 166         {
 167         .callback = video_detect_force_vendor,
 168         .ident = "Asus UL30A",
 169         .matches = {
 170                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 171                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
 172                 },
 173         },
 174         { },
 175 };
 176
 177 /*
 178  * Returns the video capabilities of a specific ACPI graphics device
 179  *
 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.
 183  */
 184 long acpi_video_get_capabilities(acpi_handle graphics_handle)
 185 {
 186         long caps = 0;
 187         struct acpi_device *tmp_dev;
 188         acpi_status status;
 189
 190         if (acpi_video_caps_checked && graphics_handle == NULL)
 191                 return acpi_video_support;
 192
 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,
 197                                     &caps, 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.:
 203                  *
 204                  *   if (dmi_name_in_vendors("XY")) {
 205                  *      acpi_video_support |=
 206                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 207                  *}
 208                  */
 209
 210                 dmi_check_system(video_detect_dmi_table);
 211         } else {
 212                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
 213                 if (ACPI_FAILURE(status)) {
 214                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
 215                         return 0;
 216                 }
 217                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
 218                                     ACPI_UINT32_MAX, find_video, NULL,
 219                                     &caps, NULL);
 220         }
 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) : ""));
 225         return caps;
 226 }
 227 EXPORT_SYMBOL(acpi_video_get_capabilities);
 228
 229 static void acpi_video_caps_check(void)
 230 {
 231         /*
 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
 234          */
 235         if (!acpi_video_caps_checked)
 236                 acpi_video_get_capabilities(NULL);
 237 }
 238
 239 bool acpi_video_backlight_quirks(void)
 240 {
 241         return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
 242 }
 243 EXPORT_SYMBOL(acpi_video_backlight_quirks);
 244
 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
 250  */
 251 void acpi_video_dmi_promote_vendor(void)
 252 {
 253         acpi_video_caps_check();
 254         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 255 }
 256 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
 257
 258 /* To be called when a driver who previously promoted the vendor
 259  * interface */
 260 void acpi_video_dmi_demote_vendor(void)
 261 {
 262         acpi_video_caps_check();
 263         acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 264 }
 265 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
 266
 267 /* Returns true if video.ko can do backlight switching */
 268 int acpi_video_backlight_support(void)
 269 {
 270         acpi_video_caps_check();
 271
 272         /* First check for boot param -> highest prio */
 273         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
 274                 return 0;
 275         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
 276                 return 1;
 277
 278         /* Then check for DMI blacklist -> second highest prio */
 279         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
 280                 return 0;
 281         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
 282                 return 1;
 283
 284         /* Then go the default way */
 285         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 286 }
 287 EXPORT_SYMBOL(acpi_video_backlight_support);
 288
 289 /*
 290  * Use acpi_backlight=vendor/video to force that backlight switching
 291  * is processed by vendor specific acpi drivers or video.ko driver.
 292  */
 293 static int __init acpi_backlight(char *str)
 294 {
 295         if (str == NULL || *str == '\0')
 296                 return 1;
 297         else {
 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;
 304         }
 305         return 1;
 306 }
 307 __setup("acpi_backlight=", acpi_backlight);