linux.git/drivers/gpu/drm/amd/display/amdgpu_dm, branch v6.16

drm/amd/display: Disable CRTC degamma LUT for DCN401

2025-07-16T20:47:43+00:00

In DCN401 pre-blending degamma LUT isn't affecting cursor as in previous
DCN version. As this is not the behavior close to what is expected for
CRTC degamma LUT, disable CRTC degamma LUT property in this HW.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/4176
---

When enabling HDR on KDE, it takes the first CRTC 1D LUT available and
apply a color transformation (Gamma 2.2 -> PQ). AMD driver usually
advertises a CRTC degamma LUT as the first CRTC 1D LUT, but it's
actually applied pre-blending. In previous HW version, it seems to work
fine because the 1D LUT was applied to cursor too, but DCN401 presents a
different behavior and the 1D LUT isn't affecting the hardware cursor.

To address the wrong gamma on cursor with HDR (see the link), I came up
with this patch that disables CRTC degamma LUT in this hw, since it
presents a different behavior than others. With this KDE sees CRTC
regamma LUT as the first post-blending 1D LUT available. This is
actually more consistent with AMD color pipeline. It was tested by the
reporter, since I don't have the HW available for local testing and
debugging.

Melissa
---

Reviewed-by: Harry Wentland 
Signed-off-by: Melissa Wen 
Signed-off-by: Ivan Lipski 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher 
(cherry picked from commit 340231cdceec2c45995d773a358ca3c341f151aa)
Cc: stable@vger.kernel.org

drm/amd/display: Don't allow OLED to go down to fully off

2025-06-30T18:01:05+00:00

[Why]
OLED panels can be fully off, but this behavior is unexpected.

[How]
Ensure that minimum luminance is at least 1.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4338
Reviewed-by: Alex Hung 
Signed-off-by: Mario Limonciello 
Signed-off-by: Ray Wu 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher 
(cherry picked from commit 51496c7737d06a74b599d0aa7974c3d5a4b1162e)

drm/amd/display: Add sanity checks for drm_edid_raw()

2025-06-24T14:39:24+00:00

When EDID is retrieved via drm_edid_raw(), it doesn't guarantee to
return proper EDID bytes the caller wants: it may be either NULL (that
leads to an Oops) or with too long bytes over the fixed size raw_edid
array (that may lead to memory corruption).  The latter was reported
actually when connected with a bad adapter.

Add sanity checks for drm_edid_raw() to address the above corner
cases, and return EDID_BAD_INPUT accordingly.

Fixes: 48edb2a4256e ("drm/amd/display: switch amdgpu_dm_connector to use struct drm_edid")
Link: https://bugzilla.suse.com/show_bug.cgi?id=1236415
Signed-off-by: Takashi Iwai 
Signed-off-by: Alex Deucher 
(cherry picked from commit 648d3f4d209725d51900d6a3ed46b7b600140cdf)
Cc: stable@vger.kernel.org

drm/amd/display: Fix AMDGPU_MAX_BL_LEVEL value

2025-06-24T14:39:13+00:00

[Why]
commit 16dc8bc27c2a ("drm/amd/display: Export full brightness range to
userspace") adjusted the brightness range to scale to larger values, but
missed updating AMDGPU_MAX_BL_LEVEL which is needed to make sure that
scaling works properly with custom brightness curves.

[How]
As the change for max brightness of 0xFFFF only applies to devices
supporting DC, use existing DC define MAX_BACKLIGHT_LEVEL.

Fixes: 16dc8bc27c2a ("drm/amd/display: Export full brightness range to userspace")
Acked-by: Alex Deucher 
Link: https://lore.kernel.org/r/20250623171114.1156451-1-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello 
Signed-off-by: Alex Deucher 
(cherry picked from commit 5b852044eb0d3e1f1c946d32e05fcb068e0a20a0)
Cc: stable@vger.kernel.org

drm/amd/display: Export full brightness range to userspace

2025-06-18T17:08:18+00:00

[WHY]
Userspace currently is offered a range from 0-0xFF but the PWM is
programmed from 0-0xFFFF.  This can be limiting to some software
that wants to apply greater granularity.

[HOW]
Convert internally to firmware values only when mapping custom
brightness curves because these are in 0-0xFF range. Advertise full
PWM range to userspace.

Cc: Mario Limonciello 
Cc: Alex Deucher 
Reviewed-by: Roman Li 
Signed-off-by: Mario Limonciello 
Signed-off-by: Alex Hung 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher 
(cherry picked from commit 8dbd72cb790058ce52279af38a43c2b302fdd3e5)
Cc: stable@vger.kernel.org

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

2025-06-18T17:07:59+00:00

[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 
Cc: Alex Deucher 
Reviewed-by: Roman Li 
Signed-off-by: Mario Limonciello 
Signed-off-by: Alex Hung 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher 
(cherry picked from commit 148144f6d2f14b02eaaa39b86bbe023cbff350bd)
Cc: stable@vger.kernel.org

drm/amd/display: Fix default DC and AC levels

2025-06-03T19:33:38+00:00

[Why]
DC and AC levels are advertised in a percentage, not a luminance.

[How]
Scale DC and AC levels to supported values.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4221
Reviewed-by: Alex Hung 
Signed-off-by: Mario Limonciello 
Signed-off-by: Wayne Lin 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher

drm/amd/display: Add debugging message for brightness caps

2025-06-03T19:33:31+00:00

[Why]
Default BIOS brightness caps are buried in ACPI.

[How]
Add extra dynamic debug that can show default brightness caps.

Reviewed-by: Alex Hung 
Signed-off-by: Mario Limonciello 
Signed-off-by: Wayne Lin 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher

Revert "drm/amd/display: pause the workload setting in dm"

2025-05-29T14:55:47+00:00

This reverts commit 50f29ead1f1ba48983b6c5e3813b15e497714f55.

Reason for revert: cause corruption on Dell U3224KB DP2 display.

Signed-off-by: Fangzhi Zuo 
Reviewed-by: Kenneth Feng 
Acked-by: Alex Deucher 
Signed-off-by: Alex Deucher

drm/amd/display: Reuse Subvp debug option for FAMS

2025-05-29T14:54:56+00:00

FAMS is the successor to SubVP starting with DCN4x. Reuse the same
debug option to disable FAMS for debugging purposes.

Signed-off-by: Aurabindo Pillai 
Reviewed-by: Harry Wentland 
Signed-off-by: Alex Deucher