On 8/26/25 03:03, Pekka Paalanen wrote:
On Thu, 21 Aug 2025 11:54:32 -0600
Alex Hung <alex.h...@amd.com> wrote:

On 8/21/25 06:23, Xaver Hugl wrote:
We user space folks have been convinced at this point that the sRGB EOTF
is actually gamma 2.2, and not the piece-wise function. Now, if the
hardware is actually the piece-wise, then that's what should be exposed,
but I'm a bit unsure if we should do that under the name sRGB EOTF.
Maybe simply rename the enum string to "sRGB piece-wise EOTF"? In
hindsight, the naming of "srgb" in the Wayland protocol caused a lot
of confusion, it's better to be explicit about it where possible.

I will leave this to Harry to comment. He is taking a few days off so I
will check with him later.


"sRGB inverse OETF"?

Strictly speaking "sRGB piece-wise EOTF" is not a thing AFAIU.


Thanks,
pq

If an extension in future after this proposal is merged, can it be GAMMA 2.2 to be [DRM_COLOROP_1D_CURVE_GAMMA22] = "GAMMA 2.2" so it won't conflict with current name?

Meanwhile, do we agree to change "sRGB EOTF" as "sRGB Inverse OETF" as the following? or do we still want to add "piece-wise"?

diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
index 1551b86471ce..90a216c0b6ac 100644
--- a/drivers/gpu/drm/drm_colorop.c
+++ b/drivers/gpu/drm/drm_colorop.c
@@ -71,7 +71,7 @@ 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_EOTF] = "sRGB Inverse OETF",
        [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 e4250b7d8de8..ce85c52c60c8 100644
--- a/include/drm/drm_colorop.h
+++ b/include/drm/drm_colorop.h
@@ -43,7 +43,7 @@ enum drm_colorop_curve_1d_type {
        /**
         * @DRM_COLOROP_1D_CURVE_SRGB_EOTF:
         *
-        * enum string "sRGB EOTF"
+        * enum string "sRGB Inverse OETF"
         *
         * sRGB piece-wise electro-optical transfer function. Transfer
         * characteristics as defined by IEC 61966-2-1 sRGB. Equivalent

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