6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mario Limonciello <mario.limonciello@xxxxxxx>
commit b96ab339ee50470d13a1faa6ad94d2218a7cd49f upstream.
Mark reports that brightness is not restored after Xorg dpms screen blank.
This behavior was introduced by commit d9e865826c20 ("drm/amd/display:
Simplify brightness initialization") which dropped the cached backlight
value in display code, but also removed code for when the default value
read back was less than 1 nit.
Restore this code so that the backlight brightness is restored to the
correct default value in this circumstance.
Reported-by: Mark Herbert <mark.herbert42@xxxxxxxxx>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3031
Cc: stable@xxxxxxxxxxxxxxx
Cc: Camille Cho <camille.cho@xxxxxxx>
Cc: Krunoslav Kovac <krunoslav.kovac@xxxxxxx>
Cc: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Fixes: d9e865826c20 ("drm/amd/display: Simplify brightness initialization")
Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
@@ -280,8 +280,8 @@ bool set_default_brightness_aux(struct d
if (link && link->dpcd_sink_ext_caps.bits.oled == 1) {
if (!read_default_bl_aux(link, &default_backlight))
default_backlight = 150000;
- // if > 5000, it might be wrong readback
- if (default_backlight > 5000000)
+ // if < 1 nits or > 5000, it might be wrong readback
+ if (default_backlight < 1000 || default_backlight > 5000000)
default_backlight = 150000;
return edp_set_backlight_level_nits(link, true,
