Mali dp needs to disable pixel alpha blending (use layer alpha blending) to
display color formats that do not contain alpha bits per pixel
Signed-off-by: Ayan Kumar Halder <ayan.halder@xxxxxxx>
---
drivers/gpu/drm/arm/malidp_planes.c | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/arm/malidp_planes.c b/drivers/gpu/drm/arm/malidp_planes.c
index e741979..4d7d564 100644
--- a/drivers/gpu/drm/arm/malidp_planes.c
+++ b/drivers/gpu/drm/arm/malidp_planes.c
@@ -35,6 +35,9 @@
#define LAYER_COMP_MASK (0x3 << 12)
#define LAYER_COMP_PIXEL (0x3 << 12)
#define LAYER_COMP_PLANE (0x2 << 12)
+#define LAYER_ALPHA_OFFSET (16)
+#define LAYER_ALPHA_MASK (0xff)
+#define LAYER_ALPHA(x) (((x) & LAYER_ALPHA_MASK) << LAYER_ALPHA_OFFSET)
#define MALIDP_LAYER_COMPOSE 0x008
#define MALIDP_LAYER_SIZE 0x00c
#define LAYER_H_VAL(x) (((x) & 0x1fff) << 0)
@@ -268,6 +271,7 @@ static void malidp_de_plane_update(struct drm_plane *plane,
struct malidp_plane_state *ms = to_malidp_plane_state(plane->state);
u32 src_w, src_h, dest_w, dest_h, val;
int i;
+ u8 alpha_bits = plane->state->fb->format->alpha;
mp = to_malidp_plane(plane);
@@ -319,12 +323,25 @@ static void malidp_de_plane_update(struct drm_plane *plane,
if (plane->state->rotation & DRM_MODE_REFLECT_Y)
val |= LAYER_V_FLIP;
- /*
- * always enable pixel alpha blending until we have a way to change
- * blend modes
- */
val &= ~LAYER_COMP_MASK;
- val |= LAYER_COMP_PIXEL;
+ if (alpha_bits > 0) {
+
+ /*
+ * always enable pixel alpha blending until we have a way to change
+ * blend modes
+ */
+ val |= LAYER_COMP_PIXEL;
+ } else {
+
+ /*
+ * do not enable pixel alpha blending as the color channel does not
+ * have any alpha information
+ */
+ val |= LAYER_COMP_PLANE;
+
+ /* Set layer alpha coefficient to 0xff ie fully opaque */
+ val |= LAYER_ALPHA(0xff);
+ }
val &= ~LAYER_FLOWCFG(LAYER_FLOWCFG_MASK);
if (plane->state->crtc) {
--
2.7.4
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