drm/amd/display: Optimize custom brightness curve interpolation

[Why]
Custom brightness curve works by walking through all data points one
by one.  When the brightness value is at either extreme this is a lot
of data points to walk.  This is especially noticeable when moving a
brightness slider around how it can lag.

[How]
Bisect the data points to find the closest for interpolation.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Mario Limonciello 2025-08-19 11:29:05 -05:00 • committed by Alex Deucher
commit de63b05593