drm/vc4: Set premultiplied for alpha formats

Alpha formats in DRM are assumed to be premultiplied, so we should be
setting the PREMULT bit in the plane configuration for HVS.

Changes from v1:
 - Use correct has_alpha

Signed-off-by: Stefan Schake <stschake@gmail.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1520556817-97297-2-git-send-email-stschake@gmail.com

diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index c4c7af1..831e195 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -618,13 +618,14 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
                                              SCALER_POS1_SCL_HEIGHT));
        }
 
-       /* Position Word 2: Source Image Size, Alpha Mode */
+       /* Position Word 2: Source Image Size, Alpha */
        vc4_state->pos2_offset = vc4_state->dlist_count;
        vc4_dlist_write(vc4_state,
                        VC4_SET_FIELD(fb->format->has_alpha ?
                                      SCALER_POS2_ALPHA_MODE_PIPELINE :
                                      SCALER_POS2_ALPHA_MODE_FIXED,
                                      SCALER_POS2_ALPHA_MODE) |
+                       (fb->format->has_alpha ? SCALER_POS2_ALPHA_PREMULT : 0) |
                        VC4_SET_FIELD(vc4_state->src_w[0], SCALER_POS2_WIDTH) |
                        VC4_SET_FIELD(vc4_state->src_h[0], SCALER_POS2_HEIGHT));
 

diff --git a/drivers/gpu/drm/vc4/vc4_regs.h b/drivers/gpu/drm/vc4/vc4_regs.h
index b9749cb..a141496 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_regs.h
+++ b/drivers/gpu/drm/vc4/vc4_regs.h
@@ -848,6 +848,7 @@ enum hvs_pixel_format {
 #define SCALER_POS2_ALPHA_MODE_FIXED           1
 #define SCALER_POS2_ALPHA_MODE_FIXED_NONZERO   2
 #define SCALER_POS2_ALPHA_MODE_FIXED_OVER_0x07 3
+#define SCALER_POS2_ALPHA_PREMULT              BIT(29)
 
 #define SCALER_POS2_HEIGHT_MASK                        VC4_MASK(27, 16)
 #define SCALER_POS2_HEIGHT_SHIFT               16