[PATCH v9 21/23] drm/mediatek: Fix underrun in VDO1 when switches off the layer

[Hsiao Chien Sung]

Do not reset Merge while using CMDQ because reset API doesn't
wait for frame done event as CMDQ does and could lead to
underrun when the layer is switching off.

Fixes: aaf94f7c3ae6 ("drm/mediatek: Add display merge async reset control")

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
Reviewed-by: CK Hu <ck.hu at mediatek.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung at mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_merge.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_merge.c b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
index fd14a59bc951..c19fb1836034 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_merge.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
@@ -104,7 +104,7 @@ void mtk_merge_stop_cmdq(struct device *dev, struct cmdq_pkt *cmdq_pkt)
 	mtk_ddp_write(cmdq_pkt, 0, &priv->cmdq_reg, priv->regs,
 		      DISP_REG_MERGE_CTRL);
 
-	if (priv->async_clk)
+	if (!cmdq_pkt && priv->async_clk)
 		reset_control_reset(priv->reset_ctl);
 }
 
-- 
2.18.0