When enabling panel backlight, if the current backlight level
setting matches the panel's minimal, it would apply default policy to
override the current level by the panel's maximum until next request
to update brightness, this leads unexpected user confusion with
temporary full power backlight.
This odd could be reproduced as commands like these:
$ xbacklight -set 0
$ sudo sh -c 'echo mem > /sys/power/state'
(resume)
To fix this, slightly tinker the backlight level comparison from
'less-and-equal-to' to 'less-than'.
Before: (dmesg | grep backlight # with drm.debug=0xe)
[ 82.249265] [drm:intel_backlight_device_update_status [i915]] updating
intel_backlight, brightness=0/5273
[ 82.249282] [drm:intel_panel_actually_set_backlight [i915]] set backlight
PWM = 207
[ 82.249306] [drm:intel_edp_backlight_power [i915]] panel power control
backlight disable
[ 92.066041] [drm:intel_edp_backlight_off [i915]]
[ 92.270489] [drm:intel_panel_actually_set_backlight [i915]] set backlight
PWM = 0
[ 94.080434] [drm:intel_edp_backlight_on.part.25 [i915]]
[ 94.080476] [drm:intel_panel_enable_backlight [i915]] pipe A
[ 94.080539] [drm:intel_panel_actually_set_backlight [i915]] set backlight
PWM = 5273
After:
[ 72.874465] [drm:intel_backlight_device_update_status [i915]] updating
intel_backlight, brightness=0/5273
[ 72.874499] [drm:intel_panel_actually_set_backlight [i915]] set backlight
PWM = 207
[ 72.874540] [drm:intel_edp_backlight_power [i915]] panel power control
backlight disable
[ 86.807928] [drm:intel_edp_backlight_off [i915]]
[ 87.013227] [drm:intel_panel_actually_set_backlight [i915]] set backlight
PWM = 0
[ 89.001829] [drm:intel_edp_backlight_on.part.25 [i915]]
[ 89.001859] [drm:intel_panel_enable_backlight [i915]] pipe A
[ 89.001926] [drm:intel_panel_actually_set_backlight [i915]] set backlight
PWM = 207
Fixes: 13f3fbe827d0 ("fix inconsistent brightness after resume")
Signed-off-by: Harry Pan <harry....@intel.com>
---
drivers/gpu/drm/i915/intel_panel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_panel.c
b/drivers/gpu/drm/i915/intel_panel.c
index 08ab6d7..e882139 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1104,7 +1104,7 @@ void intel_panel_enable_backlight(struct intel_connector
*connector)
WARN_ON(panel->backlight.max == 0);
- if (panel->backlight.level <= panel->backlight.min) {
+ if (panel->backlight.level < panel->backlight.min) {
panel->backlight.level = panel->backlight.max;
if (panel->backlight.device)
panel->backlight.device->props.brightness =
--
2.6.6
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