drm/sun4i: Enable output signal premultiplication for DE2/DE3

Otherwise alpha value is discarded, resulting incorrect pixel apperance on the display. This also fixes missing transparency for the most bottom layer. Test applications and videos w/ w/o this patch are available at [1]. [1]: GloDroid/glodroid_tests#1 Signed-off-by: Roman Stratiienko <[email protected]> --- Changelog: V2: Added code hunk missing in v1
GloDroid · Jun 5, 2022 · 566b20b · 566b20b
1 parent ff009c1
commit 566b20b
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c
@@ -351,8 +351,9 @@ static void sun8i_mixer_mode_set(struct sunxi_engine *engine,
 	else
 		val = 0;
 
-	regmap_update_bits(engine->regs, SUN8I_MIXER_BLEND_OUTCTL(bld_base),
-			   SUN8I_MIXER_BLEND_OUTCTL_INTERLACED, val);
+	val |= SUN8I_MIXER_BLEND_OUTCTL_PREMULTIPLY;
+
+	regmap_write(engine->regs, SUN8I_MIXER_BLEND_OUTCTL(bld_base), val);
 
 	DRM_DEBUG_DRIVER("Switching display mixer interlaced mode %s\n",
 			 interlaced ? "on" : "off");

diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.h b/drivers/gpu/drm/sun4i/sun8i_mixer.h
@@ -67,6 +67,7 @@
 
 #define SUN8I_MIXER_BLEND_PREMULTIPLY_EN(pipe)	BIT(pipe)
 
+#define SUN8I_MIXER_BLEND_OUTCTL_PREMULTIPLY	BIT(0)
 #define SUN8I_MIXER_BLEND_OUTCTL_INTERLACED	BIT(1)
 
 #define SUN50I_MIXER_BLEND_CSC_CTL_EN(ch)	BIT(ch)