Commit c20351ad authored by Raphael Gallais-Pou's avatar Raphael Gallais-Pou Committed by Philippe Cornu
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drm/stm: ltdc: add layer alpha support 



Android Hardware Composer supports alpha values applied to layers.
Enabling non-opaque layers for the STM CRTC could help offload GPU
resources for screen composition.

Signed-off-by: default avatarRaphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Acked-by: default avatarYannick Fertre <yannick.fertre@foss.st.com>
Reviewed-by: default avatarYannick Fertre <yannick.fertre@foss.st.com>
Signed-off-by: default avatarPhilippe Cornu <philippe.cornu@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210907151534.6013-1-raphael.gallais-pou@foss.st.com
parent ee2cda7b

drivers/gpu/drm/stm/ltdc.c

+3 −1
Original line number Diff line number Diff line
@@ -845,7 +845,7 @@ static void ltdc_plane_atomic_update(struct drm_plane *plane, 
			LXCFBLR_CFBLL | LXCFBLR_CFBP, val);



	/* Specifies the constant alpha value */

	val = CONSTA_MAX;

	val = newstate->alpha >> 8;

	reg_update_bits(ldev->regs, LTDC_L1CACR + lofs, LXCACR_CONSTA, val);



	/* Specifies the blending factors */
@@ -997,6 +997,8 @@ static struct drm_plane *ltdc_plane_create(struct drm_device *ddev, 


	drm_plane_helper_add(plane, &ltdc_plane_helper_funcs);



	drm_plane_create_alpha_property(plane);



	DRM_DEBUG_DRIVER("plane:%d created\n", plane->base.id);



	return plane;