linux/drivers/acpi/video_detect.c
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   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
  45ACPI_MODULE_NAME("video");
  46#define _COMPONENT              ACPI_VIDEO_COMPONENT
  47
  48static long acpi_video_support;
  49static bool acpi_video_caps_checked;
  50
  51static acpi_status
  52acpi_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 */
  80long 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}
 108EXPORT_SYMBOL(acpi_is_video_device);
 109
 110static acpi_status
 111find_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 */
 136static 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
 142static 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 */
 184long 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}
 227EXPORT_SYMBOL(acpi_video_get_capabilities);
 228
 229static 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
 239bool acpi_video_backlight_quirks(void)
 240{
 241        return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
 242}
 243EXPORT_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 */
 251void acpi_video_dmi_promote_vendor(void)
 252{
 253        acpi_video_caps_check();
 254        acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 255}
 256EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
 257
 258/* To be called when a driver who previously promoted the vendor
 259 * interface */
 260void acpi_video_dmi_demote_vendor(void)
 261{
 262        acpi_video_caps_check();
 263        acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 264}
 265EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
 266
 267/* Returns true if video.ko can do backlight switching */
 268int 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}
 287EXPORT_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 */
 293static 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);
 308
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