[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 4b61b8a390 ("drm/amd/display: Add debugging
message for brightness caps"), which changed max_brightness to
(max - min) and undid commit 8dbd72cb79 ("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: 4b61b8a390 ("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>
bd9e2b5b04