Re: [PATCH v5 1/2] drm: Add per-plane pixel blend mode property
On Thu, Aug 23, 2018 at 04:30:19PM +0800, Lowry Li wrote:
> Pixel blend modes represent the alpha blending equation
> selection, describing how the pixels from the current
> plane are composited with the background.
>
> Adds a pixel_blend_mode to drm_plane_state and a
> blend_mode_property to drm_plane, and related support
> functions.
>
> Defines three blend modes in drm_blend.h.
>
> Changes since v1:
> - Moves the blending equation into the DOC comment
> - Refines the comments of drm_plane_create_blend_mode_property to not
>enumerate the #defines, but instead the string values
> - Uses fg.* instead of pixel.* and plane_alpha instead of plane.alpha
> Changes since v2:
> - Refines the comments of drm_plane_create_blend_mode_property:
> 1) Puts the descriptions (after the ":") on a new line
> 2) Adds explaining why @supported_modes need PREMUL as default
> Changes since v3:
> - Refines drm_plane_create_blend_mode_property(). drm_property_add_enum()
>can calculate the index itself just fine, so no point in having the
>caller pass it in.
> - Since the current DRM assumption is that alpha is premultiplied
>as default, define DRM_MODE_BLEND_PREMULTI as 0 will be better.
> - Refines some comments.
> Changes since v4:
> - Adds comments in drm_blend.h.
> - Removes setting default value in drm_plane_create_blend_mode_property()
>as it is already in __drm_atomic_helper_plane_reset().
> - Fixes to use state->pixel_blend_mode instead of using
>plane->state->pixel_blend_mode in reset function.
> - Rebases on drm-misc-next.
>
> Reviewed-by: Liviu Dudau
Reviewed-by: Sean Paul
I've also Reviewed the userspace component in drm_hwc here:
https://gitlab.freedesktop.org/drm-hwcomposer/drm-hwcomposer/merge_requests/16#note_24690
Thanks,
Sean
> Signed-off-by: Lowry Li
> ---
> drivers/gpu/drm/drm_atomic.c| 4 ++
> drivers/gpu/drm/drm_atomic_helper.c | 1 +
> drivers/gpu/drm/drm_blend.c | 123
>
> include/drm/drm_blend.h | 6 ++
> include/drm/drm_plane.h | 9 +++
> 5 files changed, 143 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 3eb061e..d0478ab 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -895,6 +895,8 @@ static int drm_atomic_plane_set_property(struct drm_plane
> *plane,
> state->src_h = val;
> } else if (property == plane->alpha_property) {
> state->alpha = val;
> + } else if (property == plane->blend_mode_property) {
> + state->pixel_blend_mode = val;
> } else if (property == plane->rotation_property) {
> if (!is_power_of_2(val & DRM_MODE_ROTATE_MASK)) {
> DRM_DEBUG_ATOMIC("[PLANE:%d:%s] bad rotation bitmask:
> 0x%llx\n",
> @@ -968,6 +970,8 @@ static int drm_atomic_plane_set_property(struct drm_plane
> *plane,
> *val = state->src_h;
> } else if (property == plane->alpha_property) {
> *val = state->alpha;
> + } else if (property == plane->blend_mode_property) {
> + *val = state->pixel_blend_mode;
> } else if (property == plane->rotation_property) {
> *val = state->rotation;
> } else if (property == plane->zpos_property) {
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> b/drivers/gpu/drm/drm_atomic_helper.c
> index 6dd5036..284a5d2 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -3569,6 +3569,7 @@ void __drm_atomic_helper_plane_reset(struct drm_plane
> *plane,
> /* Reset the alpha value to fully opaque if it matters */
> if (plane->alpha_property)
> state->alpha = plane->alpha_property->values[1];
> + state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
>
> plane->state = state;
> }
> diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> index a16a74d..402b62d 100644
> --- a/drivers/gpu/drm/drm_blend.c
> +++ b/drivers/gpu/drm/drm_blend.c
> @@ -107,6 +107,52 @@
> * planes. Without this property the primary plane is always below the
> cursor
> * plane, and ordering between all other planes is undefined.
> *
> + * pixel blend mode:
> + * Pixel blend mode is set up with drm_plane_create_blend_mode_property().
> + * It adds a blend mode for alpha blending equation selection, describing
> + * how the pixels from the current plane are composited with the
> + * background.
> + *
> + *Three alpha blending equations are defined:
> + *
> + *"None":
> + *Blend formula that ignores the pixel alpha::
> + *
> + *out.rgb = plane_alpha * fg.rgb +
> + *(1 - plane_alpha) * bg.rgb
> + *
> + *"Pre-multiplied":
> + *Blend formula that assumes the pixel color values
> + *have been already pre-multiplied with the alpha
[PATCH v5 1/2] drm: Add per-plane pixel blend mode property
Pixel blend modes represent the alpha blending equation
selection, describing how the pixels from the current
plane are composited with the background.
Adds a pixel_blend_mode to drm_plane_state and a
blend_mode_property to drm_plane, and related support
functions.
Defines three blend modes in drm_blend.h.
Changes since v1:
- Moves the blending equation into the DOC comment
- Refines the comments of drm_plane_create_blend_mode_property to not
enumerate the #defines, but instead the string values
- Uses fg.* instead of pixel.* and plane_alpha instead of plane.alpha
Changes since v2:
- Refines the comments of drm_plane_create_blend_mode_property:
1) Puts the descriptions (after the ":") on a new line
2) Adds explaining why @supported_modes need PREMUL as default
Changes since v3:
- Refines drm_plane_create_blend_mode_property(). drm_property_add_enum()
can calculate the index itself just fine, so no point in having the
caller pass it in.
- Since the current DRM assumption is that alpha is premultiplied
as default, define DRM_MODE_BLEND_PREMULTI as 0 will be better.
- Refines some comments.
Changes since v4:
- Adds comments in drm_blend.h.
- Removes setting default value in drm_plane_create_blend_mode_property()
as it is already in __drm_atomic_helper_plane_reset().
- Fixes to use state->pixel_blend_mode instead of using
plane->state->pixel_blend_mode in reset function.
- Rebases on drm-misc-next.
Reviewed-by: Liviu Dudau
Signed-off-by: Lowry Li
---
drivers/gpu/drm/drm_atomic.c| 4 ++
drivers/gpu/drm/drm_atomic_helper.c | 1 +
drivers/gpu/drm/drm_blend.c | 123
include/drm/drm_blend.h | 6 ++
include/drm/drm_plane.h | 9 +++
5 files changed, 143 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 3eb061e..d0478ab 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -895,6 +895,8 @@ static int drm_atomic_plane_set_property(struct drm_plane
*plane,
state->src_h = val;
} else if (property == plane->alpha_property) {
state->alpha = val;
+ } else if (property == plane->blend_mode_property) {
+ state->pixel_blend_mode = val;
} else if (property == plane->rotation_property) {
if (!is_power_of_2(val & DRM_MODE_ROTATE_MASK)) {
DRM_DEBUG_ATOMIC("[PLANE:%d:%s] bad rotation bitmask:
0x%llx\n",
@@ -968,6 +970,8 @@ static int drm_atomic_plane_set_property(struct drm_plane
*plane,
*val = state->src_h;
} else if (property == plane->alpha_property) {
*val = state->alpha;
+ } else if (property == plane->blend_mode_property) {
+ *val = state->pixel_blend_mode;
} else if (property == plane->rotation_property) {
*val = state->rotation;
} else if (property == plane->zpos_property) {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c
b/drivers/gpu/drm/drm_atomic_helper.c
index 6dd5036..284a5d2 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3569,6 +3569,7 @@ void __drm_atomic_helper_plane_reset(struct drm_plane
*plane,
/* Reset the alpha value to fully opaque if it matters */
if (plane->alpha_property)
state->alpha = plane->alpha_property->values[1];
+ state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
plane->state = state;
}
diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index a16a74d..402b62d 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -107,6 +107,52 @@
* planes. Without this property the primary plane is always below the
cursor
* plane, and ordering between all other planes is undefined.
*
+ * pixel blend mode:
+ * Pixel blend mode is set up with drm_plane_create_blend_mode_property().
+ * It adds a blend mode for alpha blending equation selection, describing
+ * how the pixels from the current plane are composited with the
+ * background.
+ *
+ * Three alpha blending equations are defined:
+ *
+ * "None":
+ * Blend formula that ignores the pixel alpha::
+ *
+ * out.rgb = plane_alpha * fg.rgb +
+ * (1 - plane_alpha) * bg.rgb
+ *
+ * "Pre-multiplied":
+ * Blend formula that assumes the pixel color values
+ * have been already pre-multiplied with the alpha
+ * channel values::
+ *
+ * out.rgb = plane_alpha * fg.rgb +
+ * (1 - (plane_alpha * fg.alpha)) * bg.rgb
+ *
+ * "Coverage":
+ * Blend formula that assumes the pixel color values have not
+ * been pre-multiplied and will do so when blending them to the
+ * background color values::
+ *
+ *
