ACPI video: support buggy BIOSes with _BCQ implemented

Some buggy BIOSes implements _BCQ instead of _BQC.
Male ACPI video driver support these buggy BIOS.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 1f1625c51003..9730ec167590 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -162,6 +162,7 @@ struct acpi_video_device_cap {
         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 */
         u8 _DCS:1;              /*Return status of output device */
         u8 _DGS:1;              /*Query graphics state */
@@ -523,8 +524,10 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 {
         acpi_status status = AE_OK;
 
-        if (device->cap._BQC) {
-                status = acpi_evaluate_integer(device->dev->handle, "_BQC",
+        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) {
@@ -544,8 +547,8 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
                          * ACPI video backlight still works w/ buggy _BQC.
                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
                          */
-                        ACPI_WARNING((AE_INFO, "Evaluating _BQC failed"));
-                        device->cap._BQC = 0;
+                        ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
+                        device->cap._BQC = device->cap._BCQ = 0;
                 }
         }
 
@@ -861,6 +864,12 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
         }
         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;
         }