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
  57         if (acpi_has_method(handle, "_BCM") &&
  58             acpi_has_method(handle, "_BCL")) {
  59                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
  60                                   "support\n"));
  61                 *cap |= ACPI_VIDEO_BACKLIGHT;
  62                 if (!acpi_has_method(handle, "_BQC"))
  63                         printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
  64                                 "cannot determine initial brightness\n");
  65                 /* We have backlight support, no need to scan further */
  66                 return AE_CTRL_TERMINATE;
  67         }
  68         return 0;
  69 }
  70
  71 /* Returns true if the ACPI object is a video device which can be
  72  * handled by video.ko.
  73  * The device will get a Linux specific CID added in scan.c to
  74  * identify the device as an ACPI graphics device
  75  * Be aware that the graphics device may not be physically present
  76  * Use acpi_video_get_capabilities() to detect general ACPI video
  77  * capabilities of present cards
  78  */
  79 long acpi_is_video_device(acpi_handle handle)
  80 {
  81         long video_caps = 0;
  82
  83         /* Is this device able to support video switching ? */
  84         if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS"))
  85                 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
  86
  87         /* Is this device able to retrieve a video ROM ? */
  88         if (acpi_has_method(handle, "_ROM"))
  89                 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
  90
  91         /* Is this device able to configure which video head to be POSTed ? */
  92         if (acpi_has_method(handle, "_VPO") &&
  93             acpi_has_method(handle, "_GPD") &&
  94             acpi_has_method(handle, "_SPD"))
  95                 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
  96
  97         /* Only check for backlight functionality if one of the above hit. */
  98         if (video_caps)
  99                 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
 100                                     ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
 101                                     &video_caps, NULL);
 102
 103         return video_caps;
 104 }
 105 EXPORT_SYMBOL(acpi_is_video_device);
 106
 107 static acpi_status
 108 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 109 {
 110         long *cap = context;
 111         struct pci_dev *dev;
 112         struct acpi_device *acpi_dev;
 113
 114         const struct acpi_device_id video_ids[] = {
 115                 {ACPI_VIDEO_HID, 0},
 116                 {"", 0},
 117         };
 118         if (acpi_bus_get_device(handle, &acpi_dev))
 119                 return AE_OK;
 120
 121         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
 122                 dev = acpi_get_pci_dev(handle);
 123                 if (!dev)
 124                         return AE_OK;
 125                 pci_dev_put(dev);
 126                 *cap |= acpi_is_video_device(handle);
 127         }
 128         return AE_OK;
 129 }
 130
 131 /* Force to use vendor driver when the ACPI device is known to be
 132  * buggy */
 133 static int video_detect_force_vendor(const struct dmi_system_id *d)
 134 {
 135         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 136         return 0;
 137 }
 138
 139 static struct dmi_system_id video_detect_dmi_table[] = {
 140         /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
 141          * ACPI backlight device is used. This flag will definitively break
 142          * the backlight interface (even the vendor interface) untill next
 143          * reboot. It's why we should prevent video.ko from being used here
 144          * and we can't rely on a later call to acpi_video_unregister().
 145          */
 146         {
 147          .callback = video_detect_force_vendor,
 148          .ident = "X360",
 149          .matches = {
 150                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 151                 DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
 152                 DMI_MATCH(DMI_BOARD_NAME, "X360"),
 153                 },
 154         },
 155         {
 156         .callback = video_detect_force_vendor,
 157         .ident = "Asus UL30VT",
 158         .matches = {
 159                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 160                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
 161                 },
 162         },
 163         {
 164         .callback = video_detect_force_vendor,
 165         .ident = "Asus UL30A",
 166         .matches = {
 167                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 168                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
 169                 },
 170         },
 171         { },
 172 };
 173
 174 /*
 175  * Returns the video capabilities of a specific ACPI graphics device
 176  *
 177  * if NULL is passed as argument all ACPI devices are enumerated and
 178  * all graphics capabilities of physically present devices are
 179  * summarized and returned. This is cached and done only once.
 180  */
 181 long acpi_video_get_capabilities(acpi_handle graphics_handle)
 182 {
 183         long caps = 0;
 184         struct acpi_device *tmp_dev;
 185         acpi_status status;
 186
 187         if (acpi_video_caps_checked && graphics_handle == NULL)
 188                 return acpi_video_support;
 189
 190         if (!graphics_handle) {
 191                 /* Only do the global walk through all graphics devices once */
 192                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 193                                     ACPI_UINT32_MAX, find_video, NULL,
 194                                     &caps, NULL);
 195                 /* There might be boot param flags set already... */
 196                 acpi_video_support |= caps;
 197                 acpi_video_caps_checked = 1;
 198                 /* Add blacklists here. Be careful to use the right *DMI* bits
 199                  * to still be able to override logic via boot params, e.g.:
 200                  *
 201                  *   if (dmi_name_in_vendors("XY")) {
 202                  *      acpi_video_support |=
 203                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 204                  *}
 205                  */
 206
 207                 dmi_check_system(video_detect_dmi_table);
 208         } else {
 209                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
 210                 if (ACPI_FAILURE(status)) {
 211                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
 212                         return 0;
 213                 }
 214                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
 215                                     ACPI_UINT32_MAX, find_video, NULL,
 216                                     &caps, NULL);
 217         }
 218         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
 219                           graphics_handle ? caps : acpi_video_support,
 220                           graphics_handle ? "on device " : "in general",
 221                           graphics_handle ? acpi_device_bid(tmp_dev) : ""));
 222         return caps;
 223 }
 224 EXPORT_SYMBOL(acpi_video_get_capabilities);
 225
 226 static void acpi_video_caps_check(void)
 227 {
 228         /*
 229          * We must check whether the ACPI graphics device is physically plugged
 230          * in. Therefore this must be called after binding PCI and ACPI devices
 231          */
 232         if (!acpi_video_caps_checked)
 233                 acpi_video_get_capabilities(NULL);
 234 }
 235
 236 bool acpi_video_backlight_quirks(void)
 237 {
 238         return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
 239 }
 240 EXPORT_SYMBOL(acpi_video_backlight_quirks);
 241
 242 /* Promote the vendor interface instead of the generic video module.
 243  * This function allow DMI blacklists to be implemented by externals
 244  * platform drivers instead of putting a big blacklist in video_detect.c
 245  * After calling this function you will probably want to call
 246  * acpi_video_unregister() to make sure the video module is not loaded
 247  */
 248 void acpi_video_dmi_promote_vendor(void)
 249 {
 250         acpi_video_caps_check();
 251         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 252 }
 253 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
 254
 255 /* To be called when a driver who previously promoted the vendor
 256  * interface */
 257 void acpi_video_dmi_demote_vendor(void)
 258 {
 259         acpi_video_caps_check();
 260         acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 261 }
 262 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
 263
 264 /* Returns true if video.ko can do backlight switching */
 265 int acpi_video_backlight_support(void)
 266 {
 267         acpi_video_caps_check();
 268
 269         /* First check for boot param -> highest prio */
 270         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
 271                 return 0;
 272         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
 273                 return 1;
 274
 275         /* Then check for DMI blacklist -> second highest prio */
 276         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
 277                 return 0;
 278         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
 279                 return 1;
 280
 281         /* Then go the default way */
 282         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 283 }
 284 EXPORT_SYMBOL(acpi_video_backlight_support);
 285
 286 /*
 287  * Use acpi_backlight=vendor/video to force that backlight switching
 288  * is processed by vendor specific acpi drivers or video.ko driver.
 289  */
 290 static int __init acpi_backlight(char *str)
 291 {
 292         if (str == NULL || *str == '\0')
 293                 return 1;
 294         else {
 295                 if (!strcmp("vendor", str))
 296                         acpi_video_support |=
 297                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
 298                 if (!strcmp("video", str))
 299                         acpi_video_support |=
 300                                 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
 301         }
 302         return 1;
 303 }
 304 __setup("acpi_backlight=", acpi_backlight);