drm/omap: fix replication logic

DSS uses "replication logic" to convert color components from smaller
bit widths to bigger bit widths. Without replication logic, the color
component would be shifted and the least significant bits would be left
at 0, whereas with replication logic, the least significat bits will be
filled with the most significant bit.

For some reason omapdrm leaves replication logic always to off, which,
in the most common case, means that showing 16-bit RGB colors on 24-bit
display gives a bit darker colors than expected.

The reset value of the replication logic bit is enabled, and it should
always be set, as there's no practical reason to disable it. This patch
removes the option to disable it from omapdrm, and always sets it to
enabled in dispc.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/omapdrm/dss/dispc.c

@@ -2823,11 +2823,12 @@ static int dispc_ovl_setup_common(enum omap_plane plane,
 }
 
 static int dispc_ovl_setup(enum omap_plane plane, const struct omap_overlay_info *oi,
-		bool replication, const struct videomode *vm, bool mem_to_mem)
+		const struct videomode *vm, bool mem_to_mem)
 {
 	int r;
 	enum omap_overlay_caps caps = dss_feat_get_overlay_caps(plane);
 	enum omap_channel channel;
+	const bool replication = true;
 
 	channel = dispc_ovl_get_channel_out(plane);
 
@@ -2854,7 +2855,7 @@ int dispc_wb_setup(const struct omap_dss_writeback_info *wi,
 	enum omap_plane plane = OMAP_DSS_WB;
 	const int pos_x = 0, pos_y = 0;
 	const u8 zorder = 0, global_alpha = 0;
-	const bool replication = false;
+	const bool replication = true;
 	bool truncation;
 	int in_width = vm->hactive;
 	int in_height = vm->vactive;
@@ -4288,7 +4289,7 @@ static void dispc_errata_i734_wa(void)
 
 	/* Setup and enable GFX plane */
 	dispc_ovl_set_channel_out(OMAP_DSS_GFX, OMAP_DSS_CHANNEL_LCD);
-	dispc_ovl_setup(OMAP_DSS_GFX, &ovli, false, &i734.vm, false);
+	dispc_ovl_setup(OMAP_DSS_GFX, &ovli, &i734.vm, false);
 	dispc_ovl_enable(OMAP_DSS_GFX, true);
 
 	/* Set up and enable display manager for LCD1 */

drivers/gpu/drm/omapdrm/dss/omapdss.h

@@ -928,8 +928,7 @@ struct dispc_ops {
 	void (*ovl_set_channel_out)(enum omap_plane plane,
 			enum omap_channel channel);
 	int (*ovl_setup)(enum omap_plane plane, const struct omap_overlay_info *oi,
-			bool replication, const struct videomode *vm,
-			bool mem_to_mem);
+			const struct videomode *vm, bool mem_to_mem);
 
 	enum omap_color_mode (*ovl_get_color_modes)(enum omap_plane plane);
 };

drivers/gpu/drm/omapdrm/omap_plane.c

@@ -128,7 +128,7 @@ static void omap_plane_atomic_update(struct drm_plane *plane,
 				  omap_crtc_channel(state->crtc));
 
 	/* and finally, update omapdss: */
-	ret = priv->dispc_ops->ovl_setup(omap_plane->id, &info, false,
+	ret = priv->dispc_ops->ovl_setup(omap_plane->id, &info,
 			      omap_crtc_timings(state->crtc), false);
 	if (ret) {
 		dev_err(plane->dev->dev, "Failed to setup plane %s\n",