[RFC,v4,34/42] drm/colorop: Add PQ 125 EOTF and its inverse

Commit Message

Harry Wentland Feb. 26, 2024, 9:10 p.m. UTC

The PQ function defines a mapping of code values to nits (cd/m^2).
The max code value maps to 10,000 nits.

Windows DWM's canonical composition color space (CCCS)  defaults
to composing SDR contents to 80 nits and uses a float value of
1.0 to represent this. For this reason AMD HW hard-codes a PQ
function that is scaled by 125, yielding 80 nit PQ values for
1.0 and 10,000 nits at 125.0.

This patch introduces this scaled PQ EOTF and its inverse as
1D curve types.

Signed-off-by: Harry Wentland <[e-mail]>
---
 drivers/gpu/drm/drm_colorop.c | 2 ++
 include/drm/drm_colorop.h     | 2 ++
 2 files changed, 4 insertions(+)

Patch

diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
index 77777baa1eba..781947e42b02 100644
--- a/drivers/gpu/drm/drm_colorop.c
+++ b/drivers/gpu/drm/drm_colorop.c
@@ -40,6 +40,8 @@  static const struct drm_prop_enum_list drm_colorop_type_enum_list[] = {
 static const char * const colorop_curve_1d_type_names[] = {
 	[DRM_COLOROP_1D_CURVE_SRGB_EOTF] = "sRGB EOTF",
 	[DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF] = "sRGB Inverse EOTF",
+	[DRM_COLOROP_1D_CURVE_PQ_125_EOTF] = "PQ 125 EOTF",
+	[DRM_COLOROP_1D_CURVE_PQ_125_INV_EOTF] = "PQ 125 Inverse EOTF",
 };
 
 
diff --git a/include/drm/drm_colorop.h b/include/drm/drm_colorop.h
index 8710e550790c..e06d9ea28efd 100644
--- a/include/drm/drm_colorop.h
+++ b/include/drm/drm_colorop.h
@@ -33,6 +33,8 @@ 
 enum drm_colorop_curve_1d_type {
 	DRM_COLOROP_1D_CURVE_SRGB_EOTF,
 	DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF,
+	DRM_COLOROP_1D_CURVE_PQ_125_EOTF,
+	DRM_COLOROP_1D_CURVE_PQ_125_INV_EOTF,
 	DRM_COLOROP_1D_CURVE_COUNT
 };