Merge branch 'bugzilla-21212' into release

[firefly-linux-kernel-4.4.55.git] / drivers / acpi / video.c

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 177b4ddc34790f10360ee140da28785d38c36473..9f8c465d381b78d03dff68b2d48996420627b1b4 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -80,6 +80,13 @@ module_param(brightness_switch_enabled, bool, 0644);
 static int 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 int 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);
@@ -705,9 +712,11 @@ acpi_video_init_brightness(struct acpi_video_device *device)
                 * when invoked for the first time, i.e. level_old is invalid.
                 * set the backlight to max_level in this case
                 */
-               for (i = 2; i < br->count; i++)
-                       if (level_old == br->levels[i])
-                               level = level_old;
+               if (use_bios_initial_backlight) {
+                       for (i = 2; i < br->count; i++)
+                               if (level_old == br->levels[i])
+                                       level = level_old;
+               }
                goto set_level;
        }