[PATCH RFC v2 06/20] drm: Introduce DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE
Ariel D'Alessandro
ariel.dalessandro at collabora.com
Thu Dec 11 07:26:29 PST 2025
Harry,
On 9/29/25 6:48 AM, Harry Wentland wrote:
>
>
> On 2025-09-17 20:43, Nícolas F. R. A. Prado wrote:
>> Introduce DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE which a DRM client
>> can set to enable the usage of post-blend color pipelines instead of the
>> now deprecated CRTC color management properties: "GAMMA_LUT",
>> "DEGAMMA_LUT" and "CTM".
>>
>> Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
>> ---
>> drivers/gpu/drm/drm_atomic_uapi.c | 15 +++++++++++++++
>> drivers/gpu/drm/drm_connector.c | 1 +
>> drivers/gpu/drm/drm_crtc_internal.h | 1 +
>> drivers/gpu/drm/drm_ioctl.c | 9 +++++++++
>> drivers/gpu/drm/drm_mode_object.c | 9 +++++++++
>> include/drm/drm_file.h | 7 +++++++
>> include/uapi/drm/drm.h | 19 +++++++++++++++++++
>> 7 files changed, 61 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/
>> drm_atomic_uapi.c
>> index
>> 063c142fd9b656e228cfc660d005a3fbb4640d32..f5125fa3fa28ff2a6ff07fd7cf07d4bdf77ab738 100644
>> --- a/drivers/gpu/drm/drm_atomic_uapi.c
>> +++ b/drivers/gpu/drm/drm_atomic_uapi.c
>> @@ -452,6 +452,11 @@ static int drm_atomic_crtc_set_property(struct
>> drm_crtc *crtc,
>> } else if (property == config->prop_vrr_enabled) {
>> state->vrr_enabled = val;
>> } else if (property == config->degamma_lut_property) {
>> + if (file_priv->post_blend_color_pipeline) {
>> + drm_dbg_atomic(dev,
>> + "Setting DEGAMMA_LUT CRTC property not permitted with
>> DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE client cap\n");
>> + return -EINVAL;
>> + }
>> ret = drm_property_replace_blob_from_id(dev,
>> &state->degamma_lut,
>> val,
>> @@ -460,6 +465,11 @@ static int drm_atomic_crtc_set_property(struct
>> drm_crtc *crtc,
>> state->color_mgmt_changed |= replaced;
>> return ret;
>> } else if (property == config->ctm_property) {
>> + if (file_priv->post_blend_color_pipeline) {
>> + drm_dbg_atomic(dev,
>> + "Setting CTM CRTC property not permitted with
>> DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE client cap\n");
>> + return -EINVAL;
>> + }
>> ret = drm_property_replace_blob_from_id(dev,
>> &state->ctm,
>> val,
>> @@ -468,6 +478,11 @@ static int drm_atomic_crtc_set_property(struct
>> drm_crtc *crtc,
>> state->color_mgmt_changed |= replaced;
>> return ret;
>> } else if (property == config->gamma_lut_property) {
>> + if (file_priv->post_blend_color_pipeline) {
>> + drm_dbg_atomic(dev,
>> + "Setting GAMMA_LUT CRTC property not permitted with
>> DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE client cap\n");
>> + return -EINVAL;
>> + }
>> ret = drm_property_replace_blob_from_id(dev,
>> &state->gamma_lut,
>> val,
>> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/
>> drm_connector.c
>> index
>> 4d6dc9ebfdb5bc730b1aff7a184448af7b93f078..f58cfd2131139ff3e613adc4dbb9ddbedf724dc7 100644
>> --- a/drivers/gpu/drm/drm_connector.c
>> +++ b/drivers/gpu/drm/drm_connector.c
>> @@ -3440,6 +3440,7 @@ int drm_mode_getconnector(struct drm_device
>> *dev, void *data,
>> */
>> ret = drm_mode_object_get_properties(&connector->base,
>> file_priv->atomic,
>> file_priv->plane_color_pipeline,
>> + file_priv->post_blend_color_pipeline,
>> (uint32_t __user *)(unsigned long)(out_resp->props_ptr),
>> (uint64_t __user *)(unsigned long)(out_resp-
>> >prop_values_ptr),
>> &out_resp->count_props);
>> diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/
>> drm_crtc_internal.h
>> index
>> e3dbdcbfa385b940ec0b5476adde6146fe4afde1..c53f154e5392a10c326c844b7321666275f9ac02 100644
>> --- a/drivers/gpu/drm/drm_crtc_internal.h
>> +++ b/drivers/gpu/drm/drm_crtc_internal.h
>> @@ -169,6 +169,7 @@ void drm_mode_object_unregister(struct drm_device
>> *dev,
>> struct drm_mode_object *object);
>> int drm_mode_object_get_properties(struct drm_mode_object *obj, bool
>> atomic,
>> bool plane_color_pipeline,
>> + bool post_blend_color_pipeline,
>> uint32_t __user *prop_ptr,
>> uint64_t __user *prop_values,
>> uint32_t *arg_count_props);
>> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>> index
>> 01592d10e3465ddceddef94bc417f98d3ec12087..ea9600f5392f520a2b42ba7ef363d2f08ce19812 100644
>> --- a/drivers/gpu/drm/drm_ioctl.c
>> +++ b/drivers/gpu/drm/drm_ioctl.c
>> @@ -383,6 +383,15 @@ drm_setclientcap(struct drm_device *dev, void
>> *data, struct drm_file *file_priv)
>> return -EINVAL;
>> file_priv->plane_color_pipeline = req->value;
>> break;
>> + case DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE:
>> + if (!file_priv->atomic)
>> + return -EINVAL;
>> + if (req->value > 1)
>> + return -EINVAL;
>> + if (!drm_core_check_feature(dev,
>> DRIVER_POST_BLEND_COLOR_PIPELINE))
>> + return -EINVAL;
>> + file_priv->post_blend_color_pipeline = req->value;
>> + break;
>> default:
>> return -EINVAL;
>> }
>> diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/
>> drm_mode_object.c
>> index
>> b45d501b10c868c6d9b7a5a8760eadbd7b372a6a..5e6c3de9456b997985142a68b9cef57771a58bdc 100644
>> --- a/drivers/gpu/drm/drm_mode_object.c
>> +++ b/drivers/gpu/drm/drm_mode_object.c
>> @@ -388,6 +388,7 @@ EXPORT_SYMBOL(drm_object_property_get_default_value);
>> /* helper for getconnector and getproperties ioctls */
>> int drm_mode_object_get_properties(struct drm_mode_object *obj, bool
>> atomic,
>> bool plane_color_pipeline,
>> + bool post_blend_color_pipeline,
>> uint32_t __user *prop_ptr,
>> uint64_t __user *prop_values,
>> uint32_t *arg_count_props)
>> @@ -416,6 +417,13 @@ int drm_mode_object_get_properties(struct
>> drm_mode_object *obj, bool atomic,
>> continue;
>> }
>> + if (!post_blend_color_pipeline && obj->type ==
>> DRM_MODE_OBJECT_CRTC) {
>> + struct drm_crtc *crtc = obj_to_crtc(obj);
>> +
>> + if (prop == crtc->color_pipeline_property)
>> + continue;
>> + }
>> +
>> if (*arg_count_props > count) {
>> ret = __drm_object_property_get_value(obj, prop, &val);
>> if (ret)
>> @@ -475,6 +483,7 @@ int drm_mode_obj_get_properties_ioctl(struct
>> drm_device *dev, void *data,
>> ret = drm_mode_object_get_properties(obj, file_priv->atomic,
>> file_priv->plane_color_pipeline,
>> + file_priv->post_blend_color_pipeline,
>> (uint32_t __user *)(unsigned long)(arg->props_ptr),
>> (uint64_t __user *)(unsigned long)(arg->prop_values_ptr),
>> &arg->count_props);
>> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
>> index
>> 1a3018e4a537b3341acb50187d47371f6b781b9d..42b9a43baa18079af8ec2ea5b1484b23c497beb0 100644
>> --- a/include/drm/drm_file.h
>> +++ b/include/drm/drm_file.h
>> @@ -213,6 +213,13 @@ struct drm_file {
>> */
>> bool plane_color_pipeline;
>> + /**
>> + * @post_blend_color_pipeline:
>> + *
>> + * True if client understands post-blend color pipelines
>> + */
>> + bool post_blend_color_pipeline;
>> +
>> /**
>> * @was_master:
>> *
>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>> index
>> c6c53e57958e951204154ce41a69696a6876f0e8..f9ac10b3e4876f71005a87dedefa4aed320566f0 100644
>> --- a/include/uapi/drm/drm.h
>> +++ b/include/uapi/drm/drm.h
>> @@ -927,6 +927,25 @@ struct drm_get_cap {
>> */
>> #define DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE 7
>> +/**
>> + * DRM_CLIENT_CAP_POST_BLEND_COLOR_PIPELINE
>
> DRM_CLIENT_CAP_CRTC_COLOR_PIPELINE might be better to align
> terminology between pre- and post-blend pipelines. It would
> also make it clear that this is about the color pipeline on
> a drm_crtc (which pretty much by definition means post-
> blending).
Same answer here. Will be replacing s/post_blend/crtc in v3.
Thanks!
--
Ariel D'Alessandro
Software Engineer
Collabora Ltd.
Platinum Building, St John's Innovation Park, Cambridge CB4 0DS, UK
Registered in England & Wales, no. 5513718
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