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 c4c7af11fec523d49b4075be4e6267605f4a6198..831e1959e64d35b7898671edc7cd153fd62329ea 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 b9749cb240638ddce98a656409c6b6ffb3e44582..a141496104a6594107e45288872026f98c989e32 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