drm/cirrus: Load lut in crtc_commit

In the past the ast driver relied upon the fbdev emulation helpers to
call ->load_lut at boot-up. But since

commit b8e2b0199cc377617dc238f5106352c06dcd3fa2
Author: Peter Rosin <peda@axentia.se>
Date:   Tue Jul 4 12:36:57 2017 +0200

drm/fb-helper: factor out pseudo-palette

that's cleaned up and drivers are expected to boot into a consistent
lut state. This patch fixes that.

Fixes: b8e2b0199cc3 ("drm/fb-helper: factor out pseudo-palette")
Cc: Peter Rosin <peda@axenita.se>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org> # v4.14+
References: https://bugzilla.kernel.org/show_bug.cgi?id=198123
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180131110450.22153-1-daniel.vetter@ffwll.ch
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/cirrus/cirrus_mode.c

@@ -294,22 +294,7 @@ static void cirrus_crtc_prepare(struct drm_crtc *crtc)
 {
 }
 
-/*
- * This is called after a mode is programmed. It should reverse anything done
- * by the prepare function
- */
-static void cirrus_crtc_commit(struct drm_crtc *crtc)
-{
-}
-
-/*
- * The core can pass us a set of gamma values to program. We actually only
- * use this for 8-bit mode so can't perform smooth fades on deeper modes,
- * but it's a requirement that we provide the function
- */
-static int cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-				 u16 *blue, uint32_t size,
-				 struct drm_modeset_acquire_ctx *ctx)
+static void cirrus_crtc_load_lut(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
 	struct cirrus_device *cdev = dev->dev_private;
@@ -317,7 +302,7 @@ static int cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
 	int i;
 
 	if (!crtc->enabled)
-		return 0;
+		return;
 
 	r = crtc->gamma_store;
 	g = r + crtc->gamma_size;
@@ -330,6 +315,27 @@ static int cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
 		WREG8(PALETTE_DATA, *g++ >> 8);
 		WREG8(PALETTE_DATA, *b++ >> 8);
 	}
+}
+
+/*
+ * This is called after a mode is programmed. It should reverse anything done
+ * by the prepare function
+ */
+static void cirrus_crtc_commit(struct drm_crtc *crtc)
+{
+	cirrus_crtc_load_lut(crtc);
+}
+
+/*
+ * The core can pass us a set of gamma values to program. We actually only
+ * use this for 8-bit mode so can't perform smooth fades on deeper modes,
+ * but it's a requirement that we provide the function
+ */
+static int cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
+				 u16 *blue, uint32_t size,
+				 struct drm_modeset_acquire_ctx *ctx)
+{
+	cirrus_crtc_load_lut(crtc);
 
 	return 0;
 }