[PATCH v4 1/2] drm: Add per-plane pixel blend mode property

[Lowry Li]

On Wed, Aug 22, 2018 at 08:39:49AM -0400, Sean Paul wrote:
> On Wed, Aug 15, 2018 at 02:35:32PM +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.
> > 
> > Signed-off-by: Lowry Li <lowry.li at arm.com>
> > ---
> >  drivers/gpu/drm/drm_atomic.c        |   4 ++
> >  drivers/gpu/drm/drm_atomic_helper.c |   1 +
> >  drivers/gpu/drm/drm_blend.c         | 126 ++++++++++++++++++++++++++++++++++++
> >  include/drm/drm_blend.h             |   6 ++
> >  include/drm/drm_plane.h             |   2 +
> >  5 files changed, 139 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..563af09 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];
> > +	plane->state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
> 
> Shouldn't this be state->pixel_blend_mode instead of
> plane->state->pixel_blend_mode?
Hi Sean,
Yeah, will refine this. Thanks for your comments:) 
> >  
> >  	plane->state = state;
> >  }
> 
> /snip
> 
> -- 
> Sean Paul, Software Engineer, Google / Chromium OS

-- 
Regards,
Lowry