diff options
| author | Mario Limonciello <mario.limonciello@amd.com> | 2026-06-29 15:27:00 -0500 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2026-07-15 09:21:22 -0400 |
| commit | 86e2b8644e92df7e381c27bdbf492c19cbca8296 (patch) | |
| tree | 199019b2e04fef40752bcf284164df646593b158 /drivers | |
| parent | 977a1b821a516c16a8c07bcb284705964d0f8277 (diff) | |
| download | linux-next-86e2b8644e92df7e381c27bdbf492c19cbca8296.tar.gz linux-next-86e2b8644e92df7e381c27bdbf492c19cbca8296.zip | |
drm/amd/display: Fix backlight max_brightness to match exported range
[Why]
FWTS autobrightness fails on eDP panels because actual_brightness can
read higher than the advertised max_brightness (e.g. 63576 vs 62451).
The conversion helpers expose the firmware PWM range to userspace as
[0..max]. But max_brightness is advertised as (max - min), which is
smaller. So reading the level can return a value above max_brightness.
This regressed in commit 4b61b8a39051 ("drm/amd/display: Add debugging
message for brightness caps"), which changed max_brightness to
(max - min) and undid commit 8dbd72cb7900 ("drm/amd/display: Export full
brightness range to userspace").
[How]
Advertise max_brightness as max, and scale the initial AC/DC brightness
against max too. Update the KUnit expectations to match.
Fixes: 4b61b8a39051 ("drm/amd/display: Add debugging message for brightness caps")
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: George Zhang <george.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit bd9e2b5b0473c75abc0f4134dfe79ecbfb16610d)
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 18145d78334f..ff337de44f7a 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -5563,11 +5563,11 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) caps = &dm->backlight_caps[aconnector->bl_idx]; if (get_brightness_range(caps, &min, &max)) { if (power_supply_is_system_supplied() > 0) - props.brightness = DIV_ROUND_CLOSEST((max - min) * caps->ac_level, 100); + props.brightness = DIV_ROUND_CLOSEST(max * caps->ac_level, 100); else - props.brightness = DIV_ROUND_CLOSEST((max - min) * caps->dc_level, 100); + props.brightness = DIV_ROUND_CLOSEST(max * caps->dc_level, 100); /* min is zero, so max needs to be adjusted */ - props.max_brightness = max - min; + props.max_brightness = max; drm_dbg(drm, "Backlight caps: min: %d, max: %d, ac %d, dc %d\n", min, max, caps->ac_level, caps->dc_level); } else |