[PATCH] drm/mediatek: Fix missing configuration flags in mtk_crtc_ddp_config()

["Jason-JH.Lin" <jason-jh.lin@xxxxxxxxxxxx>]

In mtk_crtc_ddp_config(), mtk_crtc will use some configuration flags to
generate instructions to cmdq_handle, such as:
  state->pending_config
  mtk_crtc->pending_planes
  plane_state->pending.config
  mtk_crtc->pending_async_planes
  plane_state->pending.async_config

These configuration flags may be set to false when a GCE IRQ comes calling
ddp_cmdq_cb(). This may result in missing prepare instructions,
especially if mtk_crtc_update_config() with the flase need_vblank (no need
to wait for vblank) cases.

Therefore, use the mtk_crtc->config_updating flag set at the beginning of
mtk_crtc_update_config() to ensure that these configuration flags won't be
changed when the mtk_crtc_ddp_config() is preparing instructions.

Fixes: 7f82d9c43879 ("drm/mediatek: Clear pending flag when cmdq packet is done")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_crtc.c | 34 +++++++++++++++--------------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
index 6f34f573e127..bc3bf0c3edd9 100644
--- a/drivers/gpu/drm/mediatek/mtk_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
@@ -314,30 +314,32 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 
 	state = to_mtk_crtc_state(mtk_crtc->base.state);
 
-	state->pending_config = false;
+	if (!mtk_crtc->config_updating) {
+		state->pending_config = false;
 
-	if (mtk_crtc->pending_planes) {
-		for (i = 0; i < mtk_crtc->layer_nr; i++) {
-			struct drm_plane *plane = &mtk_crtc->planes[i];
-			struct mtk_plane_state *plane_state;
+		if (mtk_crtc->pending_planes) {
+			for (i = 0; i < mtk_crtc->layer_nr; i++) {
+				struct drm_plane *plane = &mtk_crtc->planes[i];
+				struct mtk_plane_state *plane_state;
 
-			plane_state = to_mtk_plane_state(plane->state);
+				plane_state = to_mtk_plane_state(plane->state);
 
-			plane_state->pending.config = false;
+				plane_state->pending.config = false;
+			}
+			mtk_crtc->pending_planes = false;
 		}
-		mtk_crtc->pending_planes = false;
-	}
 
-	if (mtk_crtc->pending_async_planes) {
-		for (i = 0; i < mtk_crtc->layer_nr; i++) {
-			struct drm_plane *plane = &mtk_crtc->planes[i];
-			struct mtk_plane_state *plane_state;
+		if (mtk_crtc->pending_async_planes) {
+			for (i = 0; i < mtk_crtc->layer_nr; i++) {
+				struct drm_plane *plane = &mtk_crtc->planes[i];
+				struct mtk_plane_state *plane_state;
 
-			plane_state = to_mtk_plane_state(plane->state);
+				plane_state = to_mtk_plane_state(plane->state);
 
-			plane_state->pending.async_config = false;
+				plane_state->pending.async_config = false;
+			}
+			mtk_crtc->pending_async_planes = false;
 		}
-		mtk_crtc->pending_async_planes = false;
 	}
 
 	mtk_crtc->cmdq_vblank_cnt = 0;
-- 
2.18.0