drm/amd/display: Only read ACPI backlight caps once

[WHY]
Backlight caps are read already in amdgpu_dm_update_backlight_caps().
They may be updated by update_connector_ext_caps(). Reading again when
registering backlight device may cause wrong values to be used.

[HOW]
Use backlight caps already registered to the dm.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Roman Li <roman.li@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Mario Limonciello 2025-05-29 11:33:44 -05:00 • committed by Alex Deucher
commit 148144f6d2