linux/drivers/gpu/drm/amd/display
Matthew Schwartz a490c8d77d drm/amd/display: Only restore backlight after amdgpu_dm_init or dm_resume
On clients that utilize AMD_PRIVATE_COLOR properties for HDR support,
brightness sliders can include a hardware controlled portion and a
gamma-based portion. This is the case on the Steam Deck OLED when using
gamescope with Steam as a client.

When a user sets a brightness level while HDR is active, the gamma-based
portion and/or hardware portion are adjusted to achieve the desired
brightness. However, when a modeset takes place while the gamma-based
portion is in-use, restoring the hardware brightness level overrides the
user's overall brightness level and results in a mismatch between what
the slider reports and the display's current brightness.

To avoid overriding gamma-based brightness, only restore HW backlight
level after boot or resume. This ensures that the backlight level is
set correctly after the DC layer resets it while avoiding interference
with subsequent modesets.

Fixes: 7875afafba ("drm/amd/display: Fix brightness level not retained over reboot")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4551
Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2025-09-18 16:59:34 -04:00
..
amdgpu_dm drm/amd/display: Only restore backlight after amdgpu_dm_init or dm_resume 2025-09-18 16:59:34 -04:00
dc drm/amd/display: Disable VRR on DCE 6 2025-09-15 17:04:28 -04:00
dmub drm/amd/display: Fix DMCUB loading sequence for DCN3.2 2025-09-15 16:57:21 -04:00
include drm/amd/display: add more cyan skillfish devices 2025-08-04 14:36:50 -04:00
modules drm/amd/display: Add HDCP policy control 2025-09-05 17:38:40 -04:00
Kconfig drm/amd/display: add CEC notifier to amdgpu driver 2025-01-10 11:58:57 -05:00
Makefile drm/amd/display: Add Component To Handle Bounding Box Values and IP Caps 2025-08-29 10:14:02 -04:00