Merge tag 'dmaengine-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw...

[mirror_ubuntu-zesty-kernel.git] / drivers / acpi / video.c

/*
 *  video.c - ACPI Video Driver ($Revision:$)
 *
 *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
 *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
 *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/input.h>
#include <linux/backlight.h>
#include <linux/thermal.h>
#include <linux/sort.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/dmi.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <linux/suspend.h>
#include <acpi/video.h>

#define PREFIX "ACPI: "

#define ACPI_VIDEO_BUS_NAME             "Video Bus"
#define ACPI_VIDEO_DEVICE_NAME          "Video Device"
#define ACPI_VIDEO_NOTIFY_SWITCH        0x80
#define ACPI_VIDEO_NOTIFY_PROBE         0x81
#define ACPI_VIDEO_NOTIFY_CYCLE         0x82
#define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT   0x83
#define ACPI_VIDEO_NOTIFY_PREV_OUTPUT   0x84

#define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS      0x85
#define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS        0x86
#define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS        0x87
#define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS       0x88
#define ACPI_VIDEO_NOTIFY_DISPLAY_OFF           0x89

#define MAX_NAME_LEN    20

#define _COMPONENT              ACPI_VIDEO_COMPONENT
ACPI_MODULE_NAME("video");

MODULE_AUTHOR("Bruno Ducrot");
MODULE_DESCRIPTION("ACPI Video Driver");
MODULE_LICENSE("GPL");

static bool brightness_switch_enabled = 1;
module_param(brightness_switch_enabled, bool, 0644);

/*
 * By default, we don't allow duplicate ACPI video bus devices
 * under the same VGA controller
 */
static bool allow_duplicates;
module_param(allow_duplicates, bool, 0644);

/*
 * Some BIOSes claim they use minimum backlight at boot,
 * and this may bring dimming screen after boot
 */
static bool use_bios_initial_backlight = 1;
module_param(use_bios_initial_backlight, bool, 0644);

static int register_count = 0;
static int acpi_video_bus_add(struct acpi_device *device);
static int acpi_video_bus_remove(struct acpi_device *device, int type);
static void acpi_video_bus_notify(struct acpi_device *device, u32 event);

static const struct acpi_device_id video_device_ids[] = {
        {ACPI_VIDEO_HID, 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, video_device_ids);

static struct acpi_driver acpi_video_bus = {
        .name = "video",
        .class = ACPI_VIDEO_CLASS,
        .ids = video_device_ids,
        .ops = {
                .add = acpi_video_bus_add,
                .remove = acpi_video_bus_remove,
                .notify = acpi_video_bus_notify,
                },
};

struct acpi_video_bus_flags {
        u8 multihead:1;         /* can switch video heads */
        u8 rom:1;               /* can retrieve a video rom */
        u8 post:1;              /* can configure the head to */
        u8 reserved:5;
};

struct acpi_video_bus_cap {
        u8 _DOS:1;              /*Enable/Disable output switching */
        u8 _DOD:1;              /*Enumerate all devices attached to display adapter */
        u8 _ROM:1;              /*Get ROM Data */
        u8 _GPD:1;              /*Get POST Device */
        u8 _SPD:1;              /*Set POST Device */
        u8 _VPO:1;              /*Video POST Options */
        u8 reserved:2;
};

struct acpi_video_device_attrib {
        u32 display_index:4;    /* A zero-based instance of the Display */
        u32 display_port_attachment:4;  /*This field differentiates the display type */
        u32 display_type:4;     /*Describe the specific type in use */
        u32 vendor_specific:4;  /*Chipset Vendor Specific */
        u32 bios_can_detect:1;  /*BIOS can detect the device */
        u32 depend_on_vga:1;    /*Non-VGA output device whose power is related to 
                                   the VGA device. */
        u32 pipe_id:3;          /*For VGA multiple-head devices. */
        u32 reserved:10;        /*Must be 0 */
        u32 device_id_scheme:1; /*Device ID Scheme */
};

struct acpi_video_enumerated_device {
        union {
                u32 int_val;
                struct acpi_video_device_attrib attrib;
        } value;
        struct acpi_video_device *bind_info;
};

struct acpi_video_bus {
        struct acpi_device *device;
        u8 dos_setting;
        struct acpi_video_enumerated_device *attached_array;
        u8 attached_count;
        struct acpi_video_bus_cap cap;
        struct acpi_video_bus_flags flags;
        struct list_head video_device_list;
        struct mutex device_list_lock;  /* protects video_device_list */
        struct input_dev *input;
        char phys[32];  /* for input device */
        struct notifier_block pm_nb;
};

struct acpi_video_device_flags {
        u8 crt:1;
        u8 lcd:1;
        u8 tvout:1;
        u8 dvi:1;
        u8 bios:1;
        u8 unknown:1;
        u8 reserved:2;
};

struct acpi_video_device_cap {
        u8 _ADR:1;              /*Return the unique ID */
        u8 _BCL:1;              /*Query list of brightness control levels supported */
        u8 _BCM:1;              /*Set the brightness level */
        u8 _BQC:1;              /* Get current brightness level */
        u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
        u8 _DDC:1;              /*Return the EDID for this device */
};

struct acpi_video_brightness_flags {
        u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
        u8 _BCL_reversed:1;             /* _BCL package is in a reversed order*/
        u8 _BCL_use_index:1;            /* levels in _BCL are index values */
        u8 _BCM_use_index:1;            /* input of _BCM is an index value */
        u8 _BQC_use_index:1;            /* _BQC returns an index value */
};

struct acpi_video_device_brightness {
        int curr;
        int count;
        int *levels;
        struct acpi_video_brightness_flags flags;
};

struct acpi_video_device {
        unsigned long device_id;
        struct acpi_video_device_flags flags;
        struct acpi_video_device_cap cap;
        struct list_head entry;
        struct acpi_video_bus *video;
        struct acpi_device *dev;
        struct acpi_video_device_brightness *brightness;
        struct backlight_device *backlight;
        struct thermal_cooling_device *cooling_dev;
};

static const char device_decode[][30] = {
        "motherboard VGA device",
        "PCI VGA device",
        "AGP VGA device",
        "UNKNOWN",
};

static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
static void acpi_video_device_rebind(struct acpi_video_bus *video);
static void acpi_video_device_bind(struct acpi_video_bus *video,
                                   struct acpi_video_device *device);
static int acpi_video_device_enumerate(struct acpi_video_bus *video);
static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
                        int level);
static int acpi_video_device_lcd_get_level_current(
                        struct acpi_video_device *device,
                        unsigned long long *level, int init);
static int acpi_video_get_next_level(struct acpi_video_device *device,
                                     u32 level_current, u32 event);
static int acpi_video_switch_brightness(struct acpi_video_device *device,
                                         int event);

/*backlight device sysfs support*/
static int acpi_video_get_brightness(struct backlight_device *bd)
{
        unsigned long long cur_level;
        int i;
        struct acpi_video_device *vd =
                (struct acpi_video_device *)bl_get_data(bd);

        if (acpi_video_device_lcd_get_level_current(vd, &cur_level, 0))
                return -EINVAL;
        for (i = 2; i < vd->brightness->count; i++) {
                if (vd->brightness->levels[i] == cur_level)
                        /* The first two entries are special - see page 575
                           of the ACPI spec 3.0 */
                        return i-2;
        }
        return 0;
}

static int acpi_video_set_brightness(struct backlight_device *bd)
{
        int request_level = bd->props.brightness + 2;
        struct acpi_video_device *vd =
                (struct acpi_video_device *)bl_get_data(bd);

        return acpi_video_device_lcd_set_level(vd,
                                vd->brightness->levels[request_level]);
}

static const struct backlight_ops acpi_backlight_ops = {
        .get_brightness = acpi_video_get_brightness,
        .update_status  = acpi_video_set_brightness,
};

/* thermal cooling device callbacks */
static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
                               long *state)
{
        struct acpi_device *device = cooling_dev->devdata;
        struct acpi_video_device *video = acpi_driver_data(device);

        *state = video->brightness->count - 3;
        return 0;
}

static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
                               long *state)
{
        struct acpi_device *device = cooling_dev->devdata;
        struct acpi_video_device *video = acpi_driver_data(device);
        unsigned long long level;
        int offset;

        if (acpi_video_device_lcd_get_level_current(video, &level, 0))
                return -EINVAL;
        for (offset = 2; offset < video->brightness->count; offset++)
                if (level == video->brightness->levels[offset]) {
                        *state = video->brightness->count - offset - 1;
                        return 0;
                }

        return -EINVAL;
}

static int
video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
{
        struct acpi_device *device = cooling_dev->devdata;
        struct acpi_video_device *video = acpi_driver_data(device);
        int level;

        if ( state >= video->brightness->count - 2)
                return -EINVAL;

        state = video->brightness->count - state;
        level = video->brightness->levels[state -1];
        return acpi_video_device_lcd_set_level(video, level);
}

static const struct thermal_cooling_device_ops video_cooling_ops = {
        .get_max_state = video_get_max_state,
        .get_cur_state = video_get_cur_state,
        .set_cur_state = video_set_cur_state,
};

/* --------------------------------------------------------------------------
                               Video Management
   -------------------------------------------------------------------------- */

static int
acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
                                   union acpi_object **levels)
{
        int status;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *obj;


        *levels = NULL;

        status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
        if (!ACPI_SUCCESS(status))
                return status;
        obj = (union acpi_object *)buffer.pointer;
        if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
                printk(KERN_ERR PREFIX "Invalid _BCL data\n");
                status = -EFAULT;
                goto err;
        }

        *levels = obj;

        return 0;

      err:
        kfree(buffer.pointer);

        return status;
}

static int
acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
{
        int status;
        union acpi_object arg0 = { ACPI_TYPE_INTEGER };
        struct acpi_object_list args = { 1, &arg0 };
        int state;

        arg0.integer.value = level;

        status = acpi_evaluate_object(device->dev->handle, "_BCM",
                                      &args, NULL);
        if (ACPI_FAILURE(status)) {
                ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
                return -EIO;
        }

        device->brightness->curr = level;
        for (state = 2; state < device->brightness->count; state++)
                if (level == device->brightness->levels[state]) {
                        if (device->backlight)
                                device->backlight->props.brightness = state - 2;
                        return 0;
                }

        ACPI_ERROR((AE_INFO, "Current brightness invalid"));
        return -EINVAL;
}

/*
 * For some buggy _BQC methods, we need to add a constant value to
 * the _BQC return value to get the actual current brightness level
 */

static int bqc_offset_aml_bug_workaround;
static int __init video_set_bqc_offset(const struct dmi_system_id *d)
{
        bqc_offset_aml_bug_workaround = 9;
        return 0;
}

static struct dmi_system_id video_dmi_table[] __initdata = {
        /*
         * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
         */
        {
         .callback = video_set_bqc_offset,
         .ident = "Acer Aspire 5720",
         .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
                DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
                },
        },
        {
         .callback = video_set_bqc_offset,
         .ident = "Acer Aspire 5710Z",
         .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
                DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
                },
        },
        {
         .callback = video_set_bqc_offset,
         .ident = "eMachines E510",
         .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
                DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
                },
        },
        {
         .callback = video_set_bqc_offset,
         .ident = "Acer Aspire 5315",
         .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
                DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
                },
        },
        {
         .callback = video_set_bqc_offset,
         .ident = "Acer Aspire 7720",
         .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
                DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
                },
        },
        {}
};

static int
acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
                                        unsigned long long *level, int init)
{
        acpi_status status = AE_OK;
        int i;

        if (device->cap._BQC || device->cap._BCQ) {
                char *buf = device->cap._BQC ? "_BQC" : "_BCQ";

                status = acpi_evaluate_integer(device->dev->handle, buf,
                                                NULL, level);
                if (ACPI_SUCCESS(status)) {
                        if (device->brightness->flags._BQC_use_index) {
                                if (device->brightness->flags._BCL_reversed)
                                        *level = device->brightness->count
                                                                 - 3 - (*level);
                                *level = device->brightness->levels[*level + 2];

                        }
                        *level += bqc_offset_aml_bug_workaround;
                        for (i = 2; i < device->brightness->count; i++)
                                if (device->brightness->levels[i] == *level) {
                                        device->brightness->curr = *level;
                                        return 0;
                        }
                        if (!init) {
                                /*
                                 * BQC returned an invalid level.
                                 * Stop using it.
                                 */
                                ACPI_WARNING((AE_INFO,
                                              "%s returned an invalid level",
                                              buf));
                                device->cap._BQC = device->cap._BCQ = 0;
                        }
                } else {
                        /* Fixme:
                         * should we return an error or ignore this failure?
                         * dev->brightness->curr is a cached value which stores
                         * the correct current backlight level in most cases.
                         * ACPI video backlight still works w/ buggy _BQC.
                         * http://bugzilla.kernel.org/show_bug.cgi?id=12233
                         */
                        ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
                        device->cap._BQC = device->cap._BCQ = 0;
                }
        }

        *level = device->brightness->curr;
        return 0;
}

static int
acpi_video_device_EDID(struct acpi_video_device *device,
                       union acpi_object **edid, ssize_t length)
{
        int status;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *obj;
        union acpi_object arg0 = { ACPI_TYPE_INTEGER };
        struct acpi_object_list args = { 1, &arg0 };


        *edid = NULL;

        if (!device)
                return -ENODEV;
        if (length == 128)
                arg0.integer.value = 1;
        else if (length == 256)
                arg0.integer.value = 2;
        else
                return -EINVAL;

        status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        obj = buffer.pointer;

        if (obj && obj->type == ACPI_TYPE_BUFFER)
                *edid = obj;
        else {
                printk(KERN_ERR PREFIX "Invalid _DDC data\n");
                status = -EFAULT;
                kfree(obj);
        }

        return status;
}

/* bus */

/*
 *  Arg:
 *      video           : video bus device pointer
 *      bios_flag       : 
 *              0.      The system BIOS should NOT automatically switch(toggle)
 *                      the active display output.
 *              1.      The system BIOS should automatically switch (toggle) the
 *                      active display output. No switch event.
 *              2.      The _DGS value should be locked.
 *              3.      The system BIOS should not automatically switch (toggle) the
 *                      active display output, but instead generate the display switch
 *                      event notify code.
 *      lcd_flag        :
 *              0.      The system BIOS should automatically control the brightness level
 *                      of the LCD when the power changes from AC to DC
 *              1.      The system BIOS should NOT automatically control the brightness 
 *                      level of the LCD when the power changes from AC to DC.
 * Return Value:
 *              -EINVAL wrong arg.
 */

static int
acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
{
        acpi_status status;
        union acpi_object arg0 = { ACPI_TYPE_INTEGER };
        struct acpi_object_list args = { 1, &arg0 };


        if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
                return -EINVAL;
        arg0.integer.value = (lcd_flag << 2) | bios_flag;
        video->dos_setting = arg0.integer.value;
        status = acpi_evaluate_object(video->device->handle, "_DOS",
                &args, NULL);
        if (ACPI_FAILURE(status))
                return -EIO;

        return 0;
}

/*
 * Simple comparison function used to sort backlight levels.
 */

static int
acpi_video_cmp_level(const void *a, const void *b)
{
        return *(int *)a - *(int *)b;
}

/*
 *  Arg:        
 *      device  : video output device (LCD, CRT, ..)
 *
 *  Return Value:
 *      Maximum brightness level
 *
 *  Allocate and initialize device->brightness.
 */

static int
acpi_video_init_brightness(struct acpi_video_device *device)
{
        union acpi_object *obj = NULL;
        int i, max_level = 0, count = 0, level_ac_battery = 0;
        unsigned long long level, level_old;
        union acpi_object *o;
        struct acpi_video_device_brightness *br = NULL;
        int result = -EINVAL;

        if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
                                                "LCD brightness level\n"));
                goto out;
        }

        if (obj->package.count < 2)
                goto out;

        br = kzalloc(sizeof(*br), GFP_KERNEL);
        if (!br) {
                printk(KERN_ERR "can't allocate memory\n");
                result = -ENOMEM;
                goto out;
        }

        br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
                                GFP_KERNEL);
        if (!br->levels) {
                result = -ENOMEM;
                goto out_free;
        }

        for (i = 0; i < obj->package.count; i++) {
                o = (union acpi_object *)&obj->package.elements[i];
                if (o->type != ACPI_TYPE_INTEGER) {
                        printk(KERN_ERR PREFIX "Invalid data\n");
                        continue;
                }
                br->levels[count] = (u32) o->integer.value;

                if (br->levels[count] > max_level)
                        max_level = br->levels[count];
                count++;
        }

        /*
         * some buggy BIOS don't export the levels
         * when machine is on AC/Battery in _BCL package.
         * In this case, the first two elements in _BCL packages
         * are also supported brightness levels that OS should take care of.
         */
        for (i = 2; i < count; i++) {
                if (br->levels[i] == br->levels[0])
                        level_ac_battery++;
                if (br->levels[i] == br->levels[1])
                        level_ac_battery++;
        }

        if (level_ac_battery < 2) {
                level_ac_battery = 2 - level_ac_battery;
                br->flags._BCL_no_ac_battery_levels = 1;
                for (i = (count - 1 + level_ac_battery); i >= 2; i--)
                        br->levels[i] = br->levels[i - level_ac_battery];
                count += level_ac_battery;
        } else if (level_ac_battery > 2)
                ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package\n"));

        /* Check if the _BCL package is in a reversed order */
        if (max_level == br->levels[2]) {
                br->flags._BCL_reversed = 1;
                sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
                        acpi_video_cmp_level, NULL);
        } else if (max_level != br->levels[count - 1])
                ACPI_ERROR((AE_INFO,
                            "Found unordered _BCL package\n"));

        br->count = count;
        device->brightness = br;

        /* Check the input/output of _BQC/_BCL/_BCM */
        if ((max_level < 100) && (max_level <= (count - 2)))
                br->flags._BCL_use_index = 1;

        /*
         * _BCM is always consistent with _BCL,
         * at least for all the laptops we have ever seen.
         */
        br->flags._BCM_use_index = br->flags._BCL_use_index;

        /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
        br->curr = level = max_level;

        if (!device->cap._BQC)
                goto set_level;

        result = acpi_video_device_lcd_get_level_current(device, &level_old, 1);
        if (result)
                goto out_free_levels;

        /*
         * Set the level to maximum and check if _BQC uses indexed value
         */
        result = acpi_video_device_lcd_set_level(device, max_level);
        if (result)
                goto out_free_levels;

        result = acpi_video_device_lcd_get_level_current(device, &level, 0);
        if (result)
                goto out_free_levels;

        br->flags._BQC_use_index = (level == max_level ? 0 : 1);

        if (!br->flags._BQC_use_index) {
                /*
                 * Set the backlight to the initial state.
                 * On some buggy laptops, _BQC returns an uninitialized value
                 * when invoked for the first time, i.e. level_old is invalid.
                 * set the backlight to max_level in this case
                 */
                if (use_bios_initial_backlight) {
                        for (i = 2; i < br->count; i++)
                                if (level_old == br->levels[i])
                                        level = level_old;
                }
                goto set_level;
        }

        if (br->flags._BCL_reversed)
                level_old = (br->count - 1) - level_old;
        level = br->levels[level_old];

set_level:
        result = acpi_video_device_lcd_set_level(device, level);
        if (result)
                goto out_free_levels;

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "found %d brightness levels\n", count - 2));
        kfree(obj);
        return result;

out_free_levels:
        kfree(br->levels);
out_free:
        kfree(br);
out:
        device->brightness = NULL;
        kfree(obj);
        return result;
}

/*
 *  Arg:
 *      device  : video output device (LCD, CRT, ..)
 *
 *  Return Value:
 *      None
 *
 *  Find out all required AML methods defined under the output
 *  device.
 */

static void acpi_video_device_find_cap(struct acpi_video_device *device)
{
        acpi_handle h_dummy1;

        if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle, "_ADR", &h_dummy1))) {
                device->cap._ADR = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle, "_BCL", &h_dummy1))) {
                device->cap._BCL = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle, "_BCM", &h_dummy1))) {
                device->cap._BCM = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle,"_BQC",&h_dummy1)))
                device->cap._BQC = 1;
        else if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle, "_BCQ",
                                &h_dummy1))) {
                printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
                device->cap._BCQ = 1;
        }

        if (ACPI_SUCCESS(acpi_get_handle(device->dev->handle, "_DDC", &h_dummy1))) {
                device->cap._DDC = 1;
        }

        if (acpi_video_backlight_support()) {
                struct backlight_properties props;
                struct pci_dev *pdev;
                acpi_handle acpi_parent;
                struct device *parent = NULL;
                int result;
                static int count = 0;
                char *name;

                result = acpi_video_init_brightness(device);
                if (result)
                        return;
                name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
                if (!name)
                        return;
                count++;

                acpi_get_parent(device->dev->handle, &acpi_parent);

                pdev = acpi_get_pci_dev(acpi_parent);
                if (pdev) {
                        parent = &pdev->dev;
                        pci_dev_put(pdev);
                }

                memset(&props, 0, sizeof(struct backlight_properties));
                props.type = BACKLIGHT_FIRMWARE;
                props.max_brightness = device->brightness->count - 3;
                device->backlight = backlight_device_register(name,
                                                              parent,
                                                              device,
                                                              &acpi_backlight_ops,
                                                              &props);
                kfree(name);
                if (IS_ERR(device->backlight))
                        return;

                /*
                 * Save current brightness level in case we have to restore it
                 * before acpi_video_device_lcd_set_level() is called next time.
                 */
                device->backlight->props.brightness =
                                acpi_video_get_brightness(device->backlight);

                device->cooling_dev = thermal_cooling_device_register("LCD",
                                        device->dev, &video_cooling_ops);
                if (IS_ERR(device->cooling_dev)) {
                        /*
                         * Set cooling_dev to NULL so we don't crash trying to
                         * free it.
                         * Also, why the hell we are returning early and
                         * not attempt to register video output if cooling
                         * device registration failed?
                         * -- dtor
                         */
                        device->cooling_dev = NULL;
                        return;
                }

                dev_info(&device->dev->dev, "registered as cooling_device%d\n",
                         device->cooling_dev->id);
                result = sysfs_create_link(&device->dev->dev.kobj,
                                &device->cooling_dev->device.kobj,
                                "thermal_cooling");
                if (result)
                        printk(KERN_ERR PREFIX "Create sysfs link\n");
                result = sysfs_create_link(&device->cooling_dev->device.kobj,
                                &device->dev->dev.kobj, "device");
                if (result)
                        printk(KERN_ERR PREFIX "Create sysfs link\n");

        }
}

/*
 *  Arg:        
 *      device  : video output device (VGA)
 *
 *  Return Value:
 *      None
 *
 *  Find out all required AML methods defined under the video bus device.
 */

static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
{
        acpi_handle h_dummy1;

        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_DOS", &h_dummy1))) {
                video->cap._DOS = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_DOD", &h_dummy1))) {
                video->cap._DOD = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_ROM", &h_dummy1))) {
                video->cap._ROM = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_GPD", &h_dummy1))) {
                video->cap._GPD = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_SPD", &h_dummy1))) {
                video->cap._SPD = 1;
        }
        if (ACPI_SUCCESS(acpi_get_handle(video->device->handle, "_VPO", &h_dummy1))) {
                video->cap._VPO = 1;
        }
}

/*
 * Check whether the video bus device has required AML method to
 * support the desired features
 */

static int acpi_video_bus_check(struct acpi_video_bus *video)
{
        acpi_status status = -ENOENT;
        struct pci_dev *dev;

        if (!video)
                return -EINVAL;

        dev = acpi_get_pci_dev(video->device->handle);
        if (!dev)
                return -ENODEV;
        pci_dev_put(dev);

        /* Since there is no HID, CID and so on for VGA driver, we have
         * to check well known required nodes.
         */

        /* Does this device support video switching? */
        if (video->cap._DOS || video->cap._DOD) {
                if (!video->cap._DOS) {
                        printk(KERN_WARNING FW_BUG
                                "ACPI(%s) defines _DOD but not _DOS\n",
                                acpi_device_bid(video->device));
                }
                video->flags.multihead = 1;
                status = 0;
        }

        /* Does this device support retrieving a video ROM? */
        if (video->cap._ROM) {
                video->flags.rom = 1;
                status = 0;
        }

        /* Does this device support configuring which video device to POST? */
        if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
                video->flags.post = 1;
                status = 0;
        }

        return status;
}

/* --------------------------------------------------------------------------
                                 Driver Interface
   -------------------------------------------------------------------------- */

/* device interface */
static struct acpi_video_device_attrib*
acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
{
        struct acpi_video_enumerated_device *ids;
        int i;

        for (i = 0; i < video->attached_count; i++) {
                ids = &video->attached_array[i];
                if ((ids->value.int_val & 0xffff) == device_id)
                        return &ids->value.attrib;
        }

        return NULL;
}

static int
acpi_video_get_device_type(struct acpi_video_bus *video,
                           unsigned long device_id)
{
        struct acpi_video_enumerated_device *ids;
        int i;

        for (i = 0; i < video->attached_count; i++) {
                ids = &video->attached_array[i];
                if ((ids->value.int_val & 0xffff) == device_id)
                        return ids->value.int_val;
        }

        return 0;
}

static int
acpi_video_bus_get_one_device(struct acpi_device *device,
                              struct acpi_video_bus *video)
{
        unsigned long long device_id;
        int status, device_type;
        struct acpi_video_device *data;
        struct acpi_video_device_attrib* attribute;

        if (!device || !video)
                return -EINVAL;

        status =
            acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
        if (ACPI_SUCCESS(status)) {

                data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
                if (!data)
                        return -ENOMEM;

                strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
                strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
                device->driver_data = data;

                data->device_id = device_id;
                data->video = video;
                data->dev = device;

                attribute = acpi_video_get_device_attr(video, device_id);

                if((attribute != NULL) && attribute->device_id_scheme) {
                        switch (attribute->display_type) {
                        case ACPI_VIDEO_DISPLAY_CRT:
                                data->flags.crt = 1;
                                break;
                        case ACPI_VIDEO_DISPLAY_TV:
                                data->flags.tvout = 1;
                                break;
                        case ACPI_VIDEO_DISPLAY_DVI:
                                data->flags.dvi = 1;
                                break;
                        case ACPI_VIDEO_DISPLAY_LCD:
                                data->flags.lcd = 1;
                                break;
                        default:
                                data->flags.unknown = 1;
                                break;
                        }
                        if(attribute->bios_can_detect)
                                data->flags.bios = 1;
                } else {
                        /* Check for legacy IDs */
                        device_type = acpi_video_get_device_type(video,
                                                                 device_id);
                        /* Ignore bits 16 and 18-20 */
                        switch (device_type & 0xffe2ffff) {
                        case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
                                data->flags.crt = 1;
                                break;
                        case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
                                data->flags.lcd = 1;
                                break;
                        case ACPI_VIDEO_DISPLAY_LEGACY_TV:
                                data->flags.tvout = 1;
                                break;
                        default:
                                data->flags.unknown = 1;
                        }
                }

                acpi_video_device_bind(video, data);
                acpi_video_device_find_cap(data);

                status = acpi_install_notify_handler(device->handle,
                                                     ACPI_DEVICE_NOTIFY,
                                                     acpi_video_device_notify,
                                                     data);
                if (ACPI_FAILURE(status)) {
                        printk(KERN_ERR PREFIX
                                          "Error installing notify handler\n");
                        if(data->brightness)
                                kfree(data->brightness->levels);
                        kfree(data->brightness);
                        kfree(data);
                        return -ENODEV;
                }

                mutex_lock(&video->device_list_lock);
                list_add_tail(&data->entry, &video->video_device_list);
                mutex_unlock(&video->device_list_lock);

                return 0;
        }

        return -ENOENT;
}

/*
 *  Arg:
 *      video   : video bus device 
 *
 *  Return:
 *      none
 *  
 *  Enumerate the video device list of the video bus, 
 *  bind the ids with the corresponding video devices
 *  under the video bus.
 */

static void acpi_video_device_rebind(struct acpi_video_bus *video)
{
        struct acpi_video_device *dev;

        mutex_lock(&video->device_list_lock);

        list_for_each_entry(dev, &video->video_device_list, entry)
                acpi_video_device_bind(video, dev);

        mutex_unlock(&video->device_list_lock);
}

/*
 *  Arg:
 *      video   : video bus device 
 *      device  : video output device under the video 
 *              bus
 *
 *  Return:
 *      none
 *  
 *  Bind the ids with the corresponding video devices
 *  under the video bus.
 */

static void
acpi_video_device_bind(struct acpi_video_bus *video,
                       struct acpi_video_device *device)
{
        struct acpi_video_enumerated_device *ids;
        int i;

        for (i = 0; i < video->attached_count; i++) {
                ids = &video->attached_array[i];
                if (device->device_id == (ids->value.int_val & 0xffff)) {
                        ids->bind_info = device;
                        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
                }
        }
}

/*
 *  Arg:
 *      video   : video bus device 
 *
 *  Return:
 *      < 0     : error
 *  
 *  Call _DOD to enumerate all devices attached to display adapter
 *
 */

static int acpi_video_device_enumerate(struct acpi_video_bus *video)
{
        int status;
        int count;
        int i;
        struct acpi_video_enumerated_device *active_list;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *dod = NULL;
        union acpi_object *obj;

        status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
        if (!ACPI_SUCCESS(status)) {
                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
                return status;
        }

        dod = buffer.pointer;
        if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
                ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
                status = -EFAULT;
                goto out;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
                          dod->package.count));

        active_list = kcalloc(1 + dod->package.count,
                              sizeof(struct acpi_video_enumerated_device),
                              GFP_KERNEL);
        if (!active_list) {
                status = -ENOMEM;
                goto out;
        }

        count = 0;
        for (i = 0; i < dod->package.count; i++) {
                obj = &dod->package.elements[i];

                if (obj->type != ACPI_TYPE_INTEGER) {
                        printk(KERN_ERR PREFIX
                                "Invalid _DOD data in element %d\n", i);
                        continue;
                }

                active_list[count].value.int_val = obj->integer.value;
                active_list[count].bind_info = NULL;
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
                                  (int)obj->integer.value));
                count++;
        }

        kfree(video->attached_array);

        video->attached_array = active_list;
        video->attached_count = count;

 out:
        kfree(buffer.pointer);
        return status;
}

static int
acpi_video_get_next_level(struct acpi_video_device *device,
                          u32 level_current, u32 event)
{
        int min, max, min_above, max_below, i, l, delta = 255;
        max = max_below = 0;
        min = min_above = 255;
        /* Find closest level to level_current */
        for (i = 2; i < device->brightness->count; i++) {
                l = device->brightness->levels[i];
                if (abs(l - level_current) < abs(delta)) {
                        delta = l - level_current;
                        if (!delta)
                                break;
                }
        }
        /* Ajust level_current to closest available level */
        level_current += delta;
        for (i = 2; i < device->brightness->count; i++) {
                l = device->brightness->levels[i];
                if (l < min)
                        min = l;
                if (l > max)
                        max = l;
                if (l < min_above && l > level_current)
                        min_above = l;
                if (l > max_below && l < level_current)
                        max_below = l;
        }

        switch (event) {
        case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
                return (level_current < max) ? min_above : min;
        case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
                return (level_current < max) ? min_above : max;
        case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
                return (level_current > min) ? max_below : min;
        case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
        case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
                return 0;
        default:
                return level_current;
        }
}

static int
acpi_video_switch_brightness(struct acpi_video_device *device, int event)
{
        unsigned long long level_current, level_next;
        int result = -EINVAL;

        /* no warning message if acpi_backlight=vendor is used */
        if (!acpi_video_backlight_support())
                return 0;

        if (!device->brightness)
                goto out;

        result = acpi_video_device_lcd_get_level_current(device,
                                                         &level_current, 0);
        if (result)
                goto out;

        level_next = acpi_video_get_next_level(device, level_current, event);

        result = acpi_video_device_lcd_set_level(device, level_next);

        if (!result)
                backlight_force_update(device->backlight,
                                       BACKLIGHT_UPDATE_HOTKEY);

out:
        if (result)
                printk(KERN_ERR PREFIX "Failed to switch the brightness\n");

        return result;
}

int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
                        void **edid)
{
        struct acpi_video_bus *video;
        struct acpi_video_device *video_device;
        union acpi_object *buffer = NULL;
        acpi_status status;
        int i, length;

        if (!device || !acpi_driver_data(device))
                return -EINVAL;

        video = acpi_driver_data(device);

        for (i = 0; i < video->attached_count; i++) {
                video_device = video->attached_array[i].bind_info;
                length = 256;

                if (!video_device)
                        continue;

                if (!video_device->cap._DDC)
                        continue;

                if (type) {
                        switch (type) {
                        case ACPI_VIDEO_DISPLAY_CRT:
                                if (!video_device->flags.crt)
                                        continue;
                                break;
                        case ACPI_VIDEO_DISPLAY_TV:
                                if (!video_device->flags.tvout)
                                        continue;
                                break;
                        case ACPI_VIDEO_DISPLAY_DVI:
                                if (!video_device->flags.dvi)
                                        continue;
                                break;
                        case ACPI_VIDEO_DISPLAY_LCD:
                                if (!video_device->flags.lcd)
                                        continue;
                                break;
                        }
                } else if (video_device->device_id != device_id) {
                        continue;
                }

                status = acpi_video_device_EDID(video_device, &buffer, length);

                if (ACPI_FAILURE(status) || !buffer ||
                    buffer->type != ACPI_TYPE_BUFFER) {
                        length = 128;
                        status = acpi_video_device_EDID(video_device, &buffer,
                                                        length);
                        if (ACPI_FAILURE(status) || !buffer ||
                            buffer->type != ACPI_TYPE_BUFFER) {
                                continue;
                        }
                }

                *edid = buffer->buffer.pointer;
                return length;
        }

        return -ENODEV;
}
EXPORT_SYMBOL(acpi_video_get_edid);

static int
acpi_video_bus_get_devices(struct acpi_video_bus *video,
                           struct acpi_device *device)
{
        int status;
        struct acpi_device *dev;

        status = acpi_video_device_enumerate(video);
        if (status)
                return status;

        list_for_each_entry(dev, &device->children, node) {

                status = acpi_video_bus_get_one_device(dev, video);
                if (status) {
                        printk(KERN_WARNING PREFIX
                                        "Can't attach device\n");
                        continue;
                }
        }
        return status;
}

static int acpi_video_bus_put_one_device(struct acpi_video_device *device)
{
        acpi_status status;

        if (!device || !device->video)
                return -ENOENT;

        status = acpi_remove_notify_handler(device->dev->handle,
                                            ACPI_DEVICE_NOTIFY,
                                            acpi_video_device_notify);
        if (ACPI_FAILURE(status)) {
                printk(KERN_WARNING PREFIX
                       "Can't remove video notify handler\n");
        }
        if (device->backlight) {
                backlight_device_unregister(device->backlight);
                device->backlight = NULL;
        }
        if (device->cooling_dev) {
                sysfs_remove_link(&device->dev->dev.kobj,
                                  "thermal_cooling");
                sysfs_remove_link(&device->cooling_dev->device.kobj,
                                  "device");
                thermal_cooling_device_unregister(device->cooling_dev);
                device->cooling_dev = NULL;
        }

        return 0;
}

static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
{
        int status;
        struct acpi_video_device *dev, *next;

        mutex_lock(&video->device_list_lock);

        list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {

                status = acpi_video_bus_put_one_device(dev);
                if (ACPI_FAILURE(status))
                        printk(KERN_WARNING PREFIX
                               "hhuuhhuu bug in acpi video driver.\n");

                if (dev->brightness) {
                        kfree(dev->brightness->levels);
                        kfree(dev->brightness);
                }
                list_del(&dev->entry);
                kfree(dev);
        }

        mutex_unlock(&video->device_list_lock);

        return 0;
}

/* acpi_video interface */

static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
{
        return acpi_video_bus_DOS(video, 0, 0);
}

static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
{
        return acpi_video_bus_DOS(video, 0, 1);
}

static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
{
        struct acpi_video_bus *video = acpi_driver_data(device);
        struct input_dev *input;
        int keycode = 0;

        if (!video)
                return;

        input = video->input;

        switch (event) {
        case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
                                         * most likely via hotkey. */
                acpi_bus_generate_proc_event(device, event, 0);
                if (!acpi_notifier_call_chain(device, event, 0))
                        keycode = KEY_SWITCHVIDEOMODE;
                break;

        case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
                                         * connector. */
                acpi_video_device_enumerate(video);
                acpi_video_device_rebind(video);
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_SWITCHVIDEOMODE;
                break;

        case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_SWITCHVIDEOMODE;
                break;
        case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_VIDEO_NEXT;
                break;
        case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_VIDEO_PREV;
                break;

        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Unsupported event [0x%x]\n", event));
                break;
        }

        if (event != ACPI_VIDEO_NOTIFY_SWITCH)
                acpi_notifier_call_chain(device, event, 0);

        if (keycode) {
                input_report_key(input, keycode, 1);
                input_sync(input);
                input_report_key(input, keycode, 0);
                input_sync(input);
        }

        return;
}

static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_video_device *video_device = data;
        struct acpi_device *device = NULL;
        struct acpi_video_bus *bus;
        struct input_dev *input;
        int keycode = 0;

        if (!video_device)
                return;

        device = video_device->dev;
        bus = video_device->video;
        input = bus->input;

        switch (event) {
        case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
                if (brightness_switch_enabled)
                        acpi_video_switch_brightness(video_device, event);
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_BRIGHTNESS_CYCLE;
                break;
        case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
                if (brightness_switch_enabled)
                        acpi_video_switch_brightness(video_device, event);
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_BRIGHTNESSUP;
                break;
        case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
                if (brightness_switch_enabled)
                        acpi_video_switch_brightness(video_device, event);
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_BRIGHTNESSDOWN;
                break;
        case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
                if (brightness_switch_enabled)
                        acpi_video_switch_brightness(video_device, event);
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_BRIGHTNESS_ZERO;
                break;
        case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
                if (brightness_switch_enabled)
                        acpi_video_switch_brightness(video_device, event);
                acpi_bus_generate_proc_event(device, event, 0);
                keycode = KEY_DISPLAY_OFF;
                break;
        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Unsupported event [0x%x]\n", event));
                break;
        }

        acpi_notifier_call_chain(device, event, 0);

        if (keycode) {
                input_report_key(input, keycode, 1);
                input_sync(input);
                input_report_key(input, keycode, 0);
                input_sync(input);
        }

        return;
}

static int acpi_video_resume(struct notifier_block *nb,
                                unsigned long val, void *ign)
{
        struct acpi_video_bus *video;
        struct acpi_video_device *video_device;
        int i;

        switch (val) {
        case PM_HIBERNATION_PREPARE:
        case PM_SUSPEND_PREPARE:
        case PM_RESTORE_PREPARE:
                return NOTIFY_DONE;
        }

        video = container_of(nb, struct acpi_video_bus, pm_nb);

        dev_info(&video->device->dev, "Restoring backlight state\n");

        for (i = 0; i < video->attached_count; i++) {
                video_device = video->attached_array[i].bind_info;
                if (video_device && video_device->backlight)
                        acpi_video_set_brightness(video_device->backlight);
        }

        return NOTIFY_OK;
}

static acpi_status
acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
                        void **return_value)
{
        struct acpi_device *device = context;
        struct acpi_device *sibling;
        int result;

        if (handle == device->handle)
                return AE_CTRL_TERMINATE;

        result = acpi_bus_get_device(handle, &sibling);
        if (result)
                return AE_OK;

        if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
                        return AE_ALREADY_EXISTS;

        return AE_OK;
}

static int instance;

static int acpi_video_bus_add(struct acpi_device *device)
{
        struct acpi_video_bus *video;
        struct input_dev *input;
        int error;
        acpi_status status;

        status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
                                device->parent->handle, 1,
                                acpi_video_bus_match, NULL,
                                device, NULL);
        if (status == AE_ALREADY_EXISTS) {
                printk(KERN_WARNING FW_BUG
                        "Duplicate ACPI video bus devices for the"
                        " same VGA controller, please try module "
                        "parameter \"video.allow_duplicates=1\""
                        "if the current driver doesn't work.\n");
                if (!allow_duplicates)
                        return -ENODEV;
        }

        video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
        if (!video)
                return -ENOMEM;

        /* a hack to fix the duplicate name "VID" problem on T61 */
        if (!strcmp(device->pnp.bus_id, "VID")) {
                if (instance)
                        device->pnp.bus_id[3] = '0' + instance;
                instance ++;
        }
        /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
        if (!strcmp(device->pnp.bus_id, "VGA")) {
                if (instance)
                        device->pnp.bus_id[3] = '0' + instance;
                instance++;
        }

        video->device = device;
        strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
        strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
        device->driver_data = video;

        acpi_video_bus_find_cap(video);
        error = acpi_video_bus_check(video);
        if (error)
                goto err_free_video;

        mutex_init(&video->device_list_lock);
        INIT_LIST_HEAD(&video->video_device_list);

        error = acpi_video_bus_get_devices(video, device);
        if (error)
                goto err_free_video;

        video->input = input = input_allocate_device();
        if (!input) {
                error = -ENOMEM;
                goto err_put_video;
        }

        error = acpi_video_bus_start_devices(video);
        if (error)
                goto err_free_input_dev;

        snprintf(video->phys, sizeof(video->phys),
                "%s/video/input0", acpi_device_hid(video->device));

        input->name = acpi_device_name(video->device);
        input->phys = video->phys;
        input->id.bustype = BUS_HOST;
        input->id.product = 0x06;
        input->dev.parent = &device->dev;
        input->evbit[0] = BIT(EV_KEY);
        set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
        set_bit(KEY_VIDEO_NEXT, input->keybit);
        set_bit(KEY_VIDEO_PREV, input->keybit);
        set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
        set_bit(KEY_BRIGHTNESSUP, input->keybit);
        set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
        set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
        set_bit(KEY_DISPLAY_OFF, input->keybit);

        error = input_register_device(input);
        if (error)
                goto err_stop_video;

        printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
               ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
               video->flags.multihead ? "yes" : "no",
               video->flags.rom ? "yes" : "no",
               video->flags.post ? "yes" : "no");

        video->pm_nb.notifier_call = acpi_video_resume;
        video->pm_nb.priority = 0;
        error = register_pm_notifier(&video->pm_nb);
        if (error)
                goto err_unregister_input_dev;

        return 0;

 err_unregister_input_dev:
        input_unregister_device(input);
 err_stop_video:
        acpi_video_bus_stop_devices(video);
 err_free_input_dev:
        input_free_device(input);
 err_put_video:
        acpi_video_bus_put_devices(video);
        kfree(video->attached_array);
 err_free_video:
        kfree(video);
        device->driver_data = NULL;

        return error;
}

static int acpi_video_bus_remove(struct acpi_device *device, int type)
{
        struct acpi_video_bus *video = NULL;


        if (!device || !acpi_driver_data(device))
                return -EINVAL;

        video = acpi_driver_data(device);

        unregister_pm_notifier(&video->pm_nb);

        acpi_video_bus_stop_devices(video);
        acpi_video_bus_put_devices(video);

        input_unregister_device(video->input);
        kfree(video->attached_array);
        kfree(video);

        return 0;
}

static int __init intel_opregion_present(void)
{
#if defined(CONFIG_DRM_I915) || defined(CONFIG_DRM_I915_MODULE)
        struct pci_dev *dev = NULL;
        u32 address;

        for_each_pci_dev(dev) {
                if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
                        continue;
                if (dev->vendor != PCI_VENDOR_ID_INTEL)
                        continue;
                pci_read_config_dword(dev, 0xfc, &address);
                if (!address)
                        continue;
                return 1;
        }
#endif
        return 0;
}

int acpi_video_register(void)
{
        int result = 0;
        if (register_count) {
                /*
                 * if the function of acpi_video_register is already called,
                 * don't register the acpi_vide_bus again and return no error.
                 */
                return 0;
        }

        result = acpi_bus_register_driver(&acpi_video_bus);
        if (result < 0)
                return -ENODEV;

        /*
         * When the acpi_video_bus is loaded successfully, increase
         * the counter reference.
         */
        register_count = 1;

        return 0;
}
EXPORT_SYMBOL(acpi_video_register);

void acpi_video_unregister(void)
{
        if (!register_count) {
                /*
                 * If the acpi video bus is already unloaded, don't
                 * unload it again and return directly.
                 */
                return;
        }
        acpi_bus_unregister_driver(&acpi_video_bus);

        register_count = 0;

        return;
}
EXPORT_SYMBOL(acpi_video_unregister);

/*
 * This is kind of nasty. Hardware using Intel chipsets may require
 * the video opregion code to be run first in order to initialise
 * state before any ACPI video calls are made. To handle this we defer
 * registration of the video class until the opregion code has run.
 */

static int __init acpi_video_init(void)
{
        dmi_check_system(video_dmi_table);

        if (intel_opregion_present())
                return 0;

        return acpi_video_register();
}

static void __exit acpi_video_exit(void)
{
        acpi_video_unregister();

        return;
}

module_init(acpi_video_init);
module_exit(acpi_video_exit);