These changes are the raw update to linux-4.4.6-rt14. Kernel sources
[kvmfornfv.git] / kernel / drivers / acpi / acpi_video.c
diff --git a/kernel/drivers/acpi/acpi_video.c b/kernel/drivers/acpi/acpi_video.c
new file mode 100644 (file)
index 0000000..5fdac39
--- /dev/null
@@ -0,0 +1,2128 @@
+/*
+ *  video.c - ACPI Video Driver
+ *
+ *  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.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#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 <linux/dmi.h>
+#include <linux/suspend.h>
+#include <linux/acpi.h>
+#include <acpi/video.h>
+#include <asm/uaccess.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);
+
+static int disable_backlight_sysfs_if = -1;
+module_param(disable_backlight_sysfs_if, int, 0444);
+
+static bool device_id_scheme = false;
+module_param(device_id_scheme, bool, 0444);
+
+static bool only_lcd = false;
+module_param(only_lcd, bool, 0444);
+
+static int register_count;
+static DEFINE_MUTEX(register_count_mutex);
+static struct mutex video_list_lock;
+static struct list_head video_bus_head;
+static int acpi_video_bus_add(struct acpi_device *device);
+static int acpi_video_bus_remove(struct acpi_device *device);
+static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
+void acpi_video_detect_exit(void);
+
+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;
+       bool backlight_registered;
+       u8 dos_setting;
+       struct acpi_video_enumerated_device *attached_array;
+       u8 attached_count;
+       u8 child_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 list_head entry;
+       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 notify:1;
+       u8 reserved:1;
+};
+
+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 _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 delayed_work switch_brightness_work;
+       int switch_brightness_event;
+       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, bool raw);
+static int acpi_video_get_next_level(struct acpi_video_device *device,
+                                    u32 level_current, u32 event);
+static void acpi_video_switch_brightness(struct work_struct *work);
+
+/* 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 = bl_get_data(bd);
+
+       if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
+               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 = bl_get_data(bd);
+
+       cancel_delayed_work(&vd->switch_brightness_work);
+       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, false))
+               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;
+       int state;
+
+       status = acpi_execute_simple_method(device->dev->handle,
+                                           "_BCM", level);
+       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 video_set_bqc_offset(const struct dmi_system_id *d)
+{
+       bqc_offset_aml_bug_workaround = 9;
+       return 0;
+}
+
+static int video_disable_backlight_sysfs_if(
+       const struct dmi_system_id *d)
+{
+       if (disable_backlight_sysfs_if == -1)
+               disable_backlight_sysfs_if = 1;
+       return 0;
+}
+
+static int video_set_device_id_scheme(const struct dmi_system_id *d)
+{
+       device_id_scheme = true;
+       return 0;
+}
+
+static int video_enable_only_lcd(const struct dmi_system_id *d)
+{
+       only_lcd = true;
+       return 0;
+}
+
+static struct dmi_system_id video_dmi_table[] = {
+       /*
+        * 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"),
+               },
+       },
+
+       /*
+        * Some machines have a broken acpi-video interface for brightness
+        * control, but still need an acpi_video_device_lcd_set_level() call
+        * on resume to turn the backlight power on.  We Enable backlight
+        * control on these systems, but do not register a backlight sysfs
+        * as brightness control does not work.
+        */
+       {
+        /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
+        .callback = video_disable_backlight_sysfs_if,
+        .ident = "Toshiba Portege R700",
+        .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
+               },
+       },
+       {
+        /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
+        .callback = video_disable_backlight_sysfs_if,
+        .ident = "Toshiba Portege R830",
+        .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
+               },
+       },
+       {
+        /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
+        .callback = video_disable_backlight_sysfs_if,
+        .ident = "Toshiba Satellite R830",
+        .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
+               },
+       },
+       /*
+        * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
+        * but the IDs actually follow the Device ID Scheme.
+        */
+       {
+        /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
+        .callback = video_set_device_id_scheme,
+        .ident = "ESPRIMO Mobile M9410",
+        .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
+               },
+       },
+       /*
+        * Some machines have multiple video output devices, but only the one
+        * that is the type of LCD can do the backlight control so we should not
+        * register backlight interface for other video output devices.
+        */
+       {
+        /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
+        .callback = video_enable_only_lcd,
+        .ident = "ESPRIMO Mobile M9410",
+        .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
+               },
+       },
+       {}
+};
+
+static unsigned long long
+acpi_video_bqc_value_to_level(struct acpi_video_device *device,
+                             unsigned long long bqc_value)
+{
+       unsigned long long level;
+
+       if (device->brightness->flags._BQC_use_index) {
+               /*
+                * _BQC returns an index that doesn't account for
+                * the first 2 items with special meaning, so we need
+                * to compensate for that by offsetting ourselves
+                */
+               if (device->brightness->flags._BCL_reversed)
+                       bqc_value = device->brightness->count - 3 - bqc_value;
+
+               level = device->brightness->levels[bqc_value + 2];
+       } else {
+               level = bqc_value;
+       }
+
+       level += bqc_offset_aml_bug_workaround;
+
+       return level;
+}
+
+static int
+acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
+                                       unsigned long long *level, bool raw)
+{
+       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 (raw) {
+                               /*
+                                * Caller has indicated he wants the raw
+                                * value returned by _BQC, so don't furtherly
+                                * mess with the value.
+                                */
+                               return 0;
+                       }
+
+                       *level = acpi_video_bqc_value_to_level(device, *level);
+
+                       for (i = 2; i < device->brightness->count; i++)
+                               if (device->brightness->levels[i] == *level) {
+                                       device->brightness->curr = *level;
+                                       return 0;
+                               }
+                       /*
+                        * 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;
+
+       if (!video->cap._DOS)
+               return 0;
+
+       if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
+               return -EINVAL;
+       video->dos_setting = (lcd_flag << 2) | bios_flag;
+       status = acpi_execute_simple_method(video->device->handle, "_DOS",
+                                           (lcd_flag << 2) | bios_flag);
+       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;
+}
+
+/*
+ * Decides if _BQC/_BCQ for this system is usable
+ *
+ * We do this by changing the level first and then read out the current
+ * brightness level, if the value does not match, find out if it is using
+ * index. If not, clear the _BQC/_BCQ capability.
+ */
+static int acpi_video_bqc_quirk(struct acpi_video_device *device,
+                               int max_level, int current_level)
+{
+       struct acpi_video_device_brightness *br = device->brightness;
+       int result;
+       unsigned long long level;
+       int test_level;
+
+       /* don't mess with existing known broken systems */
+       if (bqc_offset_aml_bug_workaround)
+               return 0;
+
+       /*
+        * Some systems always report current brightness level as maximum
+        * through _BQC, we need to test another value for them.
+        */
+       test_level = current_level == max_level ? br->levels[3] : max_level;
+
+       result = acpi_video_device_lcd_set_level(device, test_level);
+       if (result)
+               return result;
+
+       result = acpi_video_device_lcd_get_level_current(device, &level, true);
+       if (result)
+               return result;
+
+       if (level != test_level) {
+               /* buggy _BQC found, need to find out if it uses index */
+               if (level < br->count) {
+                       if (br->flags._BCL_reversed)
+                               level = br->count - 3 - level;
+                       if (br->levels[level + 2] == test_level)
+                               br->flags._BQC_use_index = 1;
+               }
+
+               if (!br->flags._BQC_use_index)
+                       device->cap._BQC = device->cap._BCQ = 0;
+       }
+
+       return 0;
+}
+
+
+/*
+ *  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;
+       u32 value;
+
+       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;
+               }
+               value = (u32) o->integer.value;
+               /* Skip duplicate entries */
+               if (count > 2 && br->levels[count - 1] == value)
+                       continue;
+
+               br->levels[count] = 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"));
+
+       /* 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"));
+
+       br->count = count;
+       device->brightness = br;
+
+       /* _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, true);
+       if (result)
+               goto out_free_levels;
+
+       result = acpi_video_bqc_quirk(device, max_level, level_old);
+       if (result)
+               goto out_free_levels;
+       /*
+        * cap._BQC may get cleared due to _BQC is found to be broken
+        * in acpi_video_bqc_quirk, so check again here.
+        */
+       if (!device->cap._BQC)
+               goto set_level;
+
+       level = acpi_video_bqc_value_to_level(device, level_old);
+       /*
+        * On some buggy laptops, _BQC returns an uninitialized
+        * value when invoked for the first time, i.e.
+        * level_old is invalid (no matter whether it's a level
+        * or an index). Set the backlight to max_level in this case.
+        */
+       for (i = 2; i < br->count; i++)
+               if (level == br->levels[i])
+                       break;
+       if (i == br->count || !level)
+               level = max_level;
+
+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)
+{
+       if (acpi_has_method(device->dev->handle, "_ADR"))
+               device->cap._ADR = 1;
+       if (acpi_has_method(device->dev->handle, "_BCL"))
+               device->cap._BCL = 1;
+       if (acpi_has_method(device->dev->handle, "_BCM"))
+               device->cap._BCM = 1;
+       if (acpi_has_method(device->dev->handle, "_BQC")) {
+               device->cap._BQC = 1;
+       } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
+               printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
+               device->cap._BCQ = 1;
+       }
+
+       if (acpi_has_method(device->dev->handle, "_DDC"))
+               device->cap._DDC = 1;
+}
+
+/*
+ *  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)
+{
+       if (acpi_has_method(video->device->handle, "_DOS"))
+               video->cap._DOS = 1;
+       if (acpi_has_method(video->device->handle, "_DOD"))
+               video->cap._DOD = 1;
+       if (acpi_has_method(video->device->handle, "_ROM"))
+               video->cap._ROM = 1;
+       if (acpi_has_method(video->device->handle, "_GPD"))
+               video->cap._GPD = 1;
+       if (acpi_has_method(video->device->handle, "_SPD"))
+               video->cap._SPD = 1;
+       if (acpi_has_method(video->device->handle, "_VPO"))
+               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;
+
+       status =
+           acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
+       /* Some device omits _ADR, we skip them instead of fail */
+       if (ACPI_FAILURE(status))
+               return 0;
+
+       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;
+       INIT_DELAYED_WORK(&data->switch_brightness_work,
+                         acpi_video_switch_brightness);
+
+       attribute = acpi_video_get_device_attr(video, device_id);
+
+       if (attribute && (attribute->device_id_scheme || 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);
+
+       mutex_lock(&video->device_list_lock);
+       list_add_tail(&data->entry, &video->video_device_list);
+       mutex_unlock(&video->device_list_lock);
+
+       return status;
+}
+
+/*
+ *  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));
+               }
+       }
+}
+
+static bool acpi_video_device_in_dod(struct acpi_video_device *device)
+{
+       struct acpi_video_bus *video = device->video;
+       int i;
+
+       /*
+        * If we have a broken _DOD or we have more than 8 output devices
+        * under the graphics controller node that we can't proper deal with
+        * in the operation region code currently, no need to test.
+        */
+       if (!video->attached_count || video->child_count > 8)
+               return true;
+
+       for (i = 0; i < video->attached_count; i++) {
+               if ((video->attached_array[i].value.int_val & 0xfff) ==
+                   (device->device_id & 0xfff))
+                       return true;
+       }
+
+       return false;
+}
+
+/*
+ *  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 void
+acpi_video_switch_brightness(struct work_struct *work)
+{
+       struct acpi_video_device *device = container_of(to_delayed_work(work),
+                            struct acpi_video_device, switch_brightness_work);
+       unsigned long long level_current, level_next;
+       int event = device->switch_brightness_event;
+       int result = -EINVAL;
+
+       /* no warning message if acpi_backlight=vendor or a quirk is used */
+       if (!device->backlight)
+               return;
+
+       if (!device->brightness)
+               goto out;
+
+       result = acpi_video_device_lcd_get_level_current(device,
+                                                        &level_current,
+                                                        false);
+       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");
+}
+
+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 = 0;
+       struct acpi_device *dev;
+
+       /*
+        * There are systems where video module known to work fine regardless
+        * of broken _DOD and ignoring returned value here doesn't cause
+        * any issues later.
+        */
+       acpi_video_device_enumerate(video);
+
+       list_for_each_entry(dev, &device->children, node) {
+
+               status = acpi_video_bus_get_one_device(dev, video);
+               if (status) {
+                       dev_err(&dev->dev, "Can't attach device\n");
+                       break;
+               }
+               video->child_count++;
+       }
+       return status;
+}
+
+/* acpi_video interface */
+
+/*
+ * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
+ * preform any automatic brightness change on receiving a notification.
+ */
+static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
+{
+       return acpi_video_bus_DOS(video, 0,
+                                 acpi_osi_is_win8() ? 1 : 0);
+}
+
+static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
+{
+       return acpi_video_bus_DOS(video, 0,
+                                 acpi_osi_is_win8() ? 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 || !video->input)
+               return;
+
+       input = video->input;
+
+       switch (event) {
+       case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
+                                        * most likely via hotkey. */
+               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);
+               keycode = KEY_SWITCHVIDEOMODE;
+               break;
+
+       case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
+               keycode = KEY_SWITCHVIDEOMODE;
+               break;
+       case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
+               keycode = KEY_VIDEO_NEXT;
+               break;
+       case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
+               keycode = KEY_VIDEO_PREV;
+               break;
+
+       default:
+               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                 "Unsupported event [0x%x]\n", event));
+               break;
+       }
+
+       if (acpi_notifier_call_chain(device, event, 0))
+               /* Something vetoed the keypress. */
+               keycode = 0;
+
+       if (keycode) {
+               input_report_key(input, keycode, 1);
+               input_sync(input);
+               input_report_key(input, keycode, 0);
+               input_sync(input);
+       }
+
+       return;
+}
+
+static void brightness_switch_event(struct acpi_video_device *video_device,
+                                   u32 event)
+{
+       if (!brightness_switch_enabled)
+               return;
+
+       video_device->switch_brightness_event = event;
+       schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
+}
+
+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 */
+               brightness_switch_event(video_device, event);
+               keycode = KEY_BRIGHTNESS_CYCLE;
+               break;
+       case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
+               brightness_switch_event(video_device, event);
+               keycode = KEY_BRIGHTNESSUP;
+               break;
+       case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
+               brightness_switch_event(video_device, event);
+               keycode = KEY_BRIGHTNESSDOWN;
+               break;
+       case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
+               brightness_switch_event(video_device, event);
+               keycode = KEY_BRIGHTNESS_ZERO;
+               break;
+       case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
+               brightness_switch_event(video_device, event);
+               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->brightness)
+                       acpi_video_device_lcd_set_level(video_device,
+                                       video_device->brightness->curr);
+       }
+
+       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 void acpi_video_dev_register_backlight(struct acpi_video_device *device)
+{
+       struct backlight_properties props;
+       struct pci_dev *pdev;
+       acpi_handle acpi_parent;
+       struct device *parent = NULL;
+       int result;
+       static int count;
+       char *name;
+
+       result = acpi_video_init_brightness(device);
+       if (result)
+               return;
+
+       if (disable_backlight_sysfs_if > 0)
+               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)) {
+               device->backlight = NULL;
+               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");
+}
+
+static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
+{
+       struct acpi_video_device *dev;
+       union acpi_object *levels;
+
+       mutex_lock(&video->device_list_lock);
+       list_for_each_entry(dev, &video->video_device_list, entry) {
+               if (!acpi_video_device_lcd_query_levels(dev, &levels))
+                       kfree(levels);
+       }
+       mutex_unlock(&video->device_list_lock);
+}
+
+static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
+{
+       /*
+        * Do not create backlight device for video output
+        * device that is not in the enumerated list.
+        */
+       if (!acpi_video_device_in_dod(dev)) {
+               dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
+               return false;
+       }
+
+       if (only_lcd)
+               return dev->flags.lcd;
+       return true;
+}
+
+static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
+{
+       struct acpi_video_device *dev;
+
+       if (video->backlight_registered)
+               return 0;
+
+       acpi_video_run_bcl_for_osi(video);
+
+       if (acpi_video_get_backlight_type() != acpi_backlight_video)
+               return 0;
+
+       mutex_lock(&video->device_list_lock);
+       list_for_each_entry(dev, &video->video_device_list, entry) {
+               if (acpi_video_should_register_backlight(dev))
+                       acpi_video_dev_register_backlight(dev);
+       }
+       mutex_unlock(&video->device_list_lock);
+
+       video->backlight_registered = true;
+
+       video->pm_nb.notifier_call = acpi_video_resume;
+       video->pm_nb.priority = 0;
+       return register_pm_notifier(&video->pm_nb);
+}
+
+static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
+{
+       if (device->backlight) {
+               backlight_device_unregister(device->backlight);
+               device->backlight = NULL;
+       }
+       if (device->brightness) {
+               kfree(device->brightness->levels);
+               kfree(device->brightness);
+               device->brightness = 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;
+       }
+}
+
+static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
+{
+       struct acpi_video_device *dev;
+       int error;
+
+       if (!video->backlight_registered)
+               return 0;
+
+       error = unregister_pm_notifier(&video->pm_nb);
+
+       mutex_lock(&video->device_list_lock);
+       list_for_each_entry(dev, &video->video_device_list, entry)
+               acpi_video_dev_unregister_backlight(dev);
+       mutex_unlock(&video->device_list_lock);
+
+       video->backlight_registered = false;
+
+       return error;
+}
+
+static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
+{
+       acpi_status status;
+       struct acpi_device *adev = device->dev;
+
+       status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
+                                            acpi_video_device_notify, device);
+       if (ACPI_FAILURE(status))
+               dev_err(&adev->dev, "Error installing notify handler\n");
+       else
+               device->flags.notify = 1;
+}
+
+static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
+{
+       struct input_dev *input;
+       struct acpi_video_device *dev;
+       int error;
+
+       video->input = input = input_allocate_device();
+       if (!input) {
+               error = -ENOMEM;
+               goto out;
+       }
+
+       error = acpi_video_bus_start_devices(video);
+       if (error)
+               goto err_free_input;
+
+       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 = &video->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_dev;
+
+       mutex_lock(&video->device_list_lock);
+       list_for_each_entry(dev, &video->video_device_list, entry)
+               acpi_video_dev_add_notify_handler(dev);
+       mutex_unlock(&video->device_list_lock);
+
+       return 0;
+
+err_stop_dev:
+       acpi_video_bus_stop_devices(video);
+err_free_input:
+       input_free_device(input);
+       video->input = NULL;
+out:
+       return error;
+}
+
+static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
+{
+       if (dev->flags.notify) {
+               acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
+                                          acpi_video_device_notify);
+               dev->flags.notify = 0;
+       }
+}
+
+static void acpi_video_bus_remove_notify_handler(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_dev_remove_notify_handler(dev);
+       mutex_unlock(&video->device_list_lock);
+
+       acpi_video_bus_stop_devices(video);
+       input_unregister_device(video->input);
+       video->input = NULL;
+}
+
+static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
+{
+       struct acpi_video_device *dev, *next;
+
+       mutex_lock(&video->device_list_lock);
+       list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
+               list_del(&dev->entry);
+               kfree(dev);
+       }
+       mutex_unlock(&video->device_list_lock);
+
+       return 0;
+}
+
+static int instance;
+
+static int acpi_video_bus_add(struct acpi_device *device)
+{
+       struct acpi_video_bus *video;
+       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_put_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");
+       mutex_lock(&video_list_lock);
+       list_add_tail(&video->entry, &video_bus_head);
+       mutex_unlock(&video_list_lock);
+
+       acpi_video_bus_register_backlight(video);
+       acpi_video_bus_add_notify_handler(video);
+
+       return 0;
+
+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)
+{
+       struct acpi_video_bus *video = NULL;
+
+
+       if (!device || !acpi_driver_data(device))
+               return -EINVAL;
+
+       video = acpi_driver_data(device);
+
+       acpi_video_bus_remove_notify_handler(video);
+       acpi_video_bus_unregister_backlight(video);
+       acpi_video_bus_put_devices(video);
+
+       mutex_lock(&video_list_lock);
+       list_del(&video->entry);
+       mutex_unlock(&video_list_lock);
+
+       kfree(video->attached_array);
+       kfree(video);
+
+       return 0;
+}
+
+static int __init is_i740(struct pci_dev *dev)
+{
+       if (dev->device == 0x00D1)
+               return 1;
+       if (dev->device == 0x7000)
+               return 1;
+       return 0;
+}
+
+static int __init intel_opregion_present(void)
+{
+       int opregion = 0;
+       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;
+               /* We don't want to poke around undefined i740 registers */
+               if (is_i740(dev))
+                       continue;
+               pci_read_config_dword(dev, 0xfc, &address);
+               if (!address)
+                       continue;
+               opregion = 1;
+       }
+       return opregion;
+}
+
+int acpi_video_register(void)
+{
+       int ret = 0;
+
+       mutex_lock(&register_count_mutex);
+       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.
+                */
+               goto leave;
+       }
+
+       mutex_init(&video_list_lock);
+       INIT_LIST_HEAD(&video_bus_head);
+
+       dmi_check_system(video_dmi_table);
+
+       ret = acpi_bus_register_driver(&acpi_video_bus);
+       if (ret)
+               goto leave;
+
+       /*
+        * When the acpi_video_bus is loaded successfully, increase
+        * the counter reference.
+        */
+       register_count = 1;
+
+leave:
+       mutex_unlock(&register_count_mutex);
+       return ret;
+}
+EXPORT_SYMBOL(acpi_video_register);
+
+void acpi_video_unregister(void)
+{
+       mutex_lock(&register_count_mutex);
+       if (register_count) {
+               acpi_bus_unregister_driver(&acpi_video_bus);
+               register_count = 0;
+       }
+       mutex_unlock(&register_count_mutex);
+}
+EXPORT_SYMBOL(acpi_video_unregister);
+
+void acpi_video_unregister_backlight(void)
+{
+       struct acpi_video_bus *video;
+
+       mutex_lock(&register_count_mutex);
+       if (register_count) {
+               mutex_lock(&video_list_lock);
+               list_for_each_entry(video, &video_bus_head, entry)
+                       acpi_video_bus_unregister_backlight(video);
+               mutex_unlock(&video_list_lock);
+       }
+       mutex_unlock(&register_count_mutex);
+}
+
+/*
+ * 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)
+{
+       /*
+        * Let the module load even if ACPI is disabled (e.g. due to
+        * a broken BIOS) so that i915.ko can still be loaded on such
+        * old systems without an AcpiOpRegion.
+        *
+        * acpi_video_register() will report -ENODEV later as well due
+        * to acpi_disabled when i915.ko tries to register itself afterwards.
+        */
+       if (acpi_disabled)
+               return 0;
+
+       if (intel_opregion_present())
+               return 0;
+
+       return acpi_video_register();
+}
+
+static void __exit acpi_video_exit(void)
+{
+       acpi_video_detect_exit();
+       acpi_video_unregister();
+
+       return;
+}
+
+module_init(acpi_video_init);
+module_exit(acpi_video_exit);