[V8,30/43] drm/colorop: add BT2020/BT709 OETF and Inverse OETF

Commit Message

Alex Hung March 26, 2025, 11:47 p.m. UTC

From: Harry Wentland <[e-mail]>

The BT.709 and BT.2020 OETFs are the same, the only difference
being that the BT.2020 variant is defined with more precision
for 10 and 12-bit per color encodings.

Both are used as encoding functions for video content, and are
therefore defined as OETF (opto-electronic transfer function)
instead of as EOTF (electro-optical transfer function).

Signed-off-by: Alex Hung <[e-mail]>
Signed-off-by: Harry Wentland <[e-mail]>
---
 drivers/gpu/drm/drm_colorop.c |  2 ++
 include/drm/drm_colorop.h     | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)

Comments

Simon Ser March 29, 2025, 2:53 p.m. UTC | #1

Note, this patch adds new values in the middle of the enum. This is in
general a breaking uAPI change: all enum values afterwards will get
re-numbered.

Maybe this patch should come before the PQ 125 one. In this series it
shouldn't matter either way because we're also introducing the enum, but
(1) who knows what/how distros might end up cherry-picking (2) future
patches might take inspiration from this one.

With that fixed:

Reviewed-by: Simon Ser <[e-mail]>

Patch

diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
index 914fa0fa71d1..fcb4a8d0e38d 100644
--- a/drivers/gpu/drm/drm_colorop.c
+++ b/drivers/gpu/drm/drm_colorop.c
@@ -70,6 +70,8 @@  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_BT2020_INV_OETF] = "BT.2020 Inverse OETF",
+	[DRM_COLOROP_1D_CURVE_BT2020_OETF] = "BT.2020 OETF",
 	[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 ce51ac407c70..d3a60c1beed1 100644
--- a/include/drm/drm_colorop.h
+++ b/include/drm/drm_colorop.h
@@ -59,6 +59,29 @@  enum drm_colorop_curve_1d_type {
 	 */
 	DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF,
 
+	/**
+	 * @DRM_COLOROP_1D_CURVE_BT2020_INV_OETF:
+	 *
+	 * enum string "BT.2020 Inverse OETF"
+	 *
+	 * The inverse of &DRM_COLOROP_1D_CURVE_BT2020_OETF
+	 */
+	DRM_COLOROP_1D_CURVE_BT2020_INV_OETF,
+
+	/**
+	 * @DRM_COLOROP_1D_CURVE_BT2020_OETF:
+	 *
+	 * enum string "BT.2020 OETF"
+	 *
+	 * The BT.2020/BT.709 transfer function. The BT.709 and BT.2020
+	 * transfer functions are the same, the only difference is that
+	 * BT.2020 is defined with more precision for 10 and 12-bit
+	 * encodings.
+	 *
+	 *
+	 */
+	DRM_COLOROP_1D_CURVE_BT2020_OETF,
+
 	/**
 	 * @DRM_COLOROP_1D_CURVE_PQ_125_EOTF:
 	 *