diff options
authorJeremiah Mahler <>2015-01-12 11:01:03 -0800
committerJani Nikula <>2015-01-21 18:41:55 +0200
commit326a23a5bf00b1aef0ae95e0cc6afea6edebc905 (patch)
parent65997b08c61175a4fd68af8eea0308fb77b90108 (diff)
drm/i915: fix inconsistent brightness after resume
commit 6dda730e55f412a6dfb181cae6784822ba463847 Author: Jani Nikula <> Date: Tue Jun 24 18:27:40 2014 +0300 drm/i915: respect the VBT minimum backlight brightness introduced a bug which resulted in inconsistent brightness levels on different machines. If a suspended was entered with the screen off some machines would resume with the screen at minimum brightness and others at maximum brightness. The following commands can be used to produce this behavior. xset dpms force off sleep 1 sudo systemctl suspend (resume ...) The root cause of this problem is a comparison which checks to see if the backlight level is zero when the panel is enabled. If it is zero, it is set to the maximum level. Unfortunately, not all machines have a minimum level of zero. On those machines the level is left at the minimum instead of begin set to the maximum. Fix the bug by updating the comparison to check for the minimum backlight level instead of zero. Also, expand the comparison for the possible case when the level is less than the minimum. Fixes: 6dda730e55f4 ("respect the VBT minimum backlight brightness") Signed-off-by: Jeremiah Mahler <> Signed-off-by: Jani Nikula <>
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 4d63839bd9b4..dfb783a8f2c3 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -962,7 +962,7 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
WARN_ON(panel->backlight.max == 0);
- if (panel->backlight.level == 0) {
+ if (panel->backlight.level <= panel->backlight.min) {
panel->backlight.level = panel->backlight.max;
if (panel->backlight.device)
panel->backlight.device->props.brightness =