drm/amd/display: map PWM brightness through custom backlight curve

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[Why/How]
On the PWM path, convert the userspace brightness to an input signal and
derive the target luminance from the custom backlight curve, then pass
the resulting millipercent to the power module.

This keeps PWM programming and backlight curve mapping in the power
module, aligning the Linux path with the Windows behavior.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/5723
Fixes: 3c108046e1 ("drm/amd/display: Add power module on Linux")
Assisted-by: Cursor:Claude-Opus-4.8
Signed-off-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Reviewed-by: ChiaHsuan (Tom) Chung <chiahsuan.chung@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit bc4e099caa)
Cc: stable@vger.kernel.org

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This commit is contained in:

Ray Wu 2026-09-18 11:05:46 +08:00 • committed by Alex Deucher

parent eaeac1498b

commit 51cc916648

2 changed files with 80 additions and 12 deletions

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2

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

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92

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_backlight.c

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