Re: [PATCH] drm/amd/display: add missing CSC entries for BT.2020 for DCE IPs

[Alex Hung]

On 5/28/26 13:03, Alex Deucher wrote:

On Thu, May 28, 2026 at 3:39 AM Leorize <leorize+...@disroot.org> wrote:

DCE-based hardware does not have the CSC matrices for BT.2020, which
causes the driver to fallback to the GPU built-in matrices. This does
not appear to cause any issues for RGB sinks, but causes major color
artifacts for YCbCr ones (e.g. black becomes green).

This commit adds the missing CSC matrices (taken from DC common) to DCE
CSC tables, resolving the issue.

Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/3358
Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5333
Assisted-by: oh-my-pi:GPT-5.5
Signed-off-by: Leorize <leorize+...@disroot.org>

This looks reasonable to me.  @Wentland, Harry, @Leo (Sunpeng) Li any concerns?

Alex

Reviewed-by: Alex Hung <alex.h...@amd.com>

---
  drivers/gpu/drm/amd/display/dc/dce/dce_transform.c     | 10 +++++++++-
  .../gpu/drm/amd/display/dc/dce110/dce110_opp_csc_v.c   | 10 +++++++++-
  2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c 
b/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c
index b3640682fa60..12c85c3afd6a 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c
@@ -110,7 +110,15 @@ static const struct out_csc_color_matrix 
global_color_matrix[] = {
  { COLOR_SPACE_YCBCR601_LIMITED, { 0xE00, 0xF447, 0xFDB9, 0x1000, 0x991,
         0x12C9, 0x3A6, 0x200, 0xFB47, 0xF6B9, 0xE00, 0x1000} },
  { COLOR_SPACE_YCBCR709_LIMITED, { 0xE00, 0xF349, 0xFEB7, 0x1000, 0x6CE, 
0x16E3,
-       0x24F, 0x200, 0xFCCB, 0xF535, 0xE00, 0x1000} }
+       0x24F, 0x200, 0xFCCB, 0xF535, 0xE00, 0x1000} },
+{ COLOR_SPACE_2020_RGB_FULLRANGE,
+       { 0x2000, 0, 0, 0, 0, 0x2000, 0, 0, 0, 0, 0x2000, 0} },
+{ COLOR_SPACE_2020_RGB_LIMITEDRANGE,
+       { 0x1B67, 0, 0, 0x201, 0, 0x1B67, 0, 0x201, 0, 0, 0x1B67, 0x201} },
+{ COLOR_SPACE_2020_YCBCR_LIMITED, { 0x1000, 0xF149, 0xFEB7, 0x1004, 0x0868,
+       0x15B2, 0x01E6, 0x201, 0xFB88, 0xF478, 0x1000, 0x1004} },
+{ COLOR_SPACE_2020_YCBCR_FULL, { 0x1000, 0xF149, 0xFEB7, 0x1004, 0x0868, 
0x15B2,
+       0x01E6, 0x201, 0xFB88, 0xF478, 0x1000, 0x1004} }
  };

  static bool setup_scaling_configuration(
diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_opp_csc_v.c 
b/drivers/gpu/drm/amd/display/dc/dce110/dce110_opp_csc_v.c
index cf63fac82832..1ed018aaa4bb 100644
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_opp_csc_v.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_opp_csc_v.c
@@ -88,7 +88,15 @@ static const struct out_csc_color_matrix 
global_color_matrix[] = {
  { COLOR_SPACE_YCBCR601_LIMITED, { 0xE00, 0xF447, 0xFDB9, 0x1000, 0x991,
         0x12C9, 0x3A6, 0x200, 0xFB47, 0xF6B9, 0xE00, 0x1000} },
  { COLOR_SPACE_YCBCR709_LIMITED, { 0xE00, 0xF349, 0xFEB7, 0x1000, 0x6CE, 
0x16E3,
-       0x24F, 0x200, 0xFCCB, 0xF535, 0xE00, 0x1000} }
+       0x24F, 0x200, 0xFCCB, 0xF535, 0xE00, 0x1000} },
+{ COLOR_SPACE_2020_RGB_FULLRANGE,
+       { 0x2000, 0, 0, 0, 0, 0x2000, 0, 0, 0, 0, 0x2000, 0} },
+{ COLOR_SPACE_2020_RGB_LIMITEDRANGE,
+       { 0x1B67, 0, 0, 0x201, 0, 0x1B67, 0, 0x201, 0, 0, 0x1B67, 0x201} },
+{ COLOR_SPACE_2020_YCBCR_LIMITED, { 0x1000, 0xF149, 0xFEB7, 0x1004, 0x0868,
+       0x15B2, 0x01E6, 0x201, 0xFB88, 0xF478, 0x1000, 0x1004} },
+{ COLOR_SPACE_2020_YCBCR_FULL, { 0x1000, 0xF149, 0xFEB7, 0x1004, 0x0868, 
0x15B2,
+       0x01E6, 0x201, 0xFB88, 0xF478, 0x1000, 0x1004} }
  };

  enum csc_color_mode {
--
2.54.0