[AMD Official Use Only - AMD Internal Distribution Only] > -----Original Message----- > From: dri-devel <[email protected]> On Behalf Of Sean > Anderson > Sent: Thursday, November 13, 2025 3:07 PM > To: Klymenko, Anatoliy <[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 > > Caution: This message originated from an External Source. Use proper caution > when opening attachments, clicking links, or responding. > > > On 11/13/25 18:03, Klymenko, Anatoliy wrote: > > [AMD Official Use Only - AMD Internal Distribution Only] > > > > 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; > >> + > >> + 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. > > Do you have a datasheet (or other) reference? >
Yes https://docs.amd.com/v/u/en-US/ug1085-zynq-ultrascale-trm > But in any case, DRM_MODE_BLEND_PREMULTI is mandatory even if we > don't support > it. See drm_plane_create_blend_mode_property for details. > No doubts here > --Sean Thank you, Anatoliy
