ACPI video: ignore buggy _BQC

_BQC doesn't return a value listed in _BCL method.
http://bugzilla.kernel.org/show_bug.cgi?id=13511

ingore the buggy _BQC method in this case

Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Signed-off-by: Scott Howard <showard314@gmail.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index a0cd0c7ee9e29bd2d0149ae419ec34ad16de79cc..2020907921cc36e568193edd9ea179654824b293 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -603,6 +603,7 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
                                        unsigned long long *level)
 {
        acpi_status status = AE_OK;
+       int i;
 
        if (device->cap._BQC || device->cap._BCQ) {
                char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
@@ -618,8 +619,15 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 
                        }
                        *level += bqc_offset_aml_bug_workaround;
-                       device->brightness->curr = *level;
-                       return 0;
+                       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?