[AMD Official Use Only - AMD Internal Distribution Only] > -----Original Message----- > From: Klymenko, Anatoliy > Sent: Thursday, November 13, 2025 3:04 PM > To: 'Sean Anderson' <[email protected]>; Laurent Pinchart > <[email protected]>; Tomi Valkeinen > <[email protected]>; [email protected] > Cc: [email protected]; Mike Looijmans <[email protected]>; > David Airlie <[email protected]>; Thomas Zimmermann > <[email protected]>; Maarten Lankhorst > <[email protected]>; Maxime Ripard <[email protected]>; > [email protected]; Simona Vetter <[email protected]>; Simek, > Michal <[email protected]> > Subject: RE: [PATCH 3/3] drm: zynqmp: Add blend mode property to graphics > plane > > Hi Sean, > > Thank you for the patch. > > > -----Original Message----- > > From: Sean Anderson <[email protected]> > > Sent: Thursday, November 13, 2025 12:37 PM > > To: Laurent Pinchart <[email protected]>; Tomi Valkeinen > > <[email protected]>; [email protected] > > Cc: [email protected]; Mike Looijmans <[email protected]>; > > David Airlie <[email protected]>; Thomas Zimmermann > > <[email protected]>; Maarten Lankhorst > > <[email protected]>; Klymenko, Anatoliy > > <[email protected]>; Maxime Ripard <[email protected]>; > linux- > > [email protected]; Simona Vetter <[email protected]>; Simek, > > Michal <[email protected]>; Sean Anderson > > <[email protected]> > > Subject: [PATCH 3/3] drm: zynqmp: Add blend mode property to graphics > plane > > > > Caution: This message originated from an External Source. Use proper > caution > > when opening attachments, clicking links, or responding. > > > > > > When global alpha is enabled, per-pixel alpha is ignored. Allow > > userspace to explicitly specify whether to use per-pixel alpha by > > exposing it through the blend mode property. I'm not sure whether the > > per-pixel alpha is pre-multiplied or not [1], but apparently it *must* be > > pre-multiplied so I guess we have to advertise it. > > > > [1] All we get is "The alpha value available with the graphics stream > > will define the transparency of the graphics." > > > > Signed-off-by: Sean Anderson <[email protected]> > > --- > > > > drivers/gpu/drm/xlnx/zynqmp_kms.c | 24 ++++++++++++++++++++++-- > > 1 file changed, 22 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c > > b/drivers/gpu/drm/xlnx/zynqmp_kms.c > > index 456ada9ac003..fa1cfc16db36 100644 > > --- a/drivers/gpu/drm/xlnx/zynqmp_kms.c > > +++ b/drivers/gpu/drm/xlnx/zynqmp_kms.c > > @@ -61,6 +61,13 @@ static int zynqmp_dpsub_plane_atomic_check(struct > > drm_plane *plane, > > if (!new_plane_state->crtc) > > return 0; > > > > + if (new_plane_state->pixel_blend_mode != > > DRM_MODE_BLEND_PIXEL_NONE && > > + new_plane_state->alpha >> 8 != 0xff) { > > + drm_dbg_kms(plane->dev, > > + "Plane alpha must be 1.0 when using pixel > > alpha\n"); > > + return -EINVAL; > > + } > > + > > crtc_state = drm_atomic_get_crtc_state(state, > > new_plane_state->crtc); > > if (IS_ERR(crtc_state)) > > return PTR_ERR(crtc_state); > > @@ -117,9 +124,13 @@ static void > > zynqmp_dpsub_plane_atomic_update(struct drm_plane *plane, > > > > zynqmp_disp_layer_update(layer, new_state); > > > > - if (plane->index == ZYNQMP_DPSUB_LAYER_GFX) > > - zynqmp_disp_blend_set_global_alpha(dpsub->disp, true, > > + if (plane->index == ZYNQMP_DPSUB_LAYER_GFX) { > > + bool blend = plane->state->pixel_blend_mode == > > + DRM_MODE_BLEND_PIXEL_NONE;
I would suggest adding || !plane->state->fb->format->has_alpha; pixel_blend_mode doesn't make a lot of sense for non-alpha formats but may have a negative effect on Mike's fix https://lore.kernel.org/dri-devel/[email protected]/ if user isn't careful enough around this property. > > + > > + zynqmp_disp_blend_set_global_alpha(dpsub->disp, blend, > > plane->state->alpha >> > > 8); > > + } > > > > /* > > * Unconditionally enable the layer, as it may have been disabled > > @@ -179,9 +190,18 @@ static int zynqmp_dpsub_create_planes(struct > > zynqmp_dpsub *dpsub) > > return ret; > > > > if (i == ZYNQMP_DPSUB_LAYER_GFX) { > > + unsigned int blend_modes = > > + BIT(DRM_MODE_BLEND_PIXEL_NONE) | > > + BIT(DRM_MODE_BLEND_PREMULTI); > > | BIT(DRM_MODE_BLEND_COVERAGE) - this is what implemented in the > hardware. > > > + > > ret = drm_plane_create_alpha_property(plane); > > if (ret) > > return ret; > > + > > + ret = drm_plane_create_blend_mode_property(plane, > > + > > blend_modes); > > + if (ret) > > + return ret; > > } > > } > > > > -- > > 2.35.1.1320.gc452695387.dirty > > Thank you, > Anatoliy Thank you, Anatoliy
