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Melissa Wen 340231cdce drm/amd/display: Disable CRTC degamma LUT for DCN401
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 <harry.wentland@amd.com>
Signed-off-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2025-07-15 14:07:53 -04:00
arch drm-misc-next for 6.17: 2025-06-27 09:58:05 +10:00
block block-6.16-20250614 2025-06-14 09:25:22 -07:00
certs
crypto crypto: hkdf - move to late_initcall 2025-06-11 10:59:45 +08:00
Documentation UAPI Changes: 2025-07-11 11:08:53 +02:00
drivers drm/amd/display: Disable CRTC degamma LUT for DCN401 2025-07-15 14:07:53 -04:00
fs three smb3 client fixes 2025-06-14 10:13:32 -07:00
include UAPI Changes: 2025-07-11 11:08:53 +02:00
init init: fix build warnings about export.h 2025-06-11 22:42:36 -07:00
io_uring io_uring-6.16-20250614 2025-06-14 08:44:54 -07:00
ipc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kernel posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() 2025-06-13 10:55:49 -07:00
lib scatterlist: fix extraneous '@'-sign kernel-doc notation 2025-06-11 22:42:35 -07:00
LICENSES
mm 9 hotfixes. 3 are cc:stable and the remainder address post-6.15 issues 2025-06-14 08:18:09 -07:00
net Including fixes from bluetooth and wireless. 2025-06-12 09:50:36 -07:00
rust Merge remote-tracking branch 'drm/drm-next' into drm-misc-next 2025-07-08 16:49:07 +02:00
samples - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
scripts gendwarfksyms: Fix structure type overrides 2025-06-16 00:49:48 +09:00
security KEYS: Invert FINAL_PUT bit 2025-06-11 11:57:14 -07:00
sound treewide, timers: Rename from_timer() to timer_container_of() 2025-06-08 09:07:37 +02:00
tools 9 hotfixes. 3 are cc:stable and the remainder address post-6.15 issues 2025-06-14 08:18:09 -07:00
usr
virt
.clang-format
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap Including fixes from bluetooth and wireless. 2025-06-12 09:50:36 -07:00
.pylintrc
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS UAPI Changes: 2025-07-11 11:08:53 +02:00
Makefile Linux 6.16-rc2 2025-06-15 13:49:41 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
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