drm/mediatek: Fix underrun in VDO1 when switches off the layer

[ Upstream commit 73b5ab27ab2ee616f2709dc212c2b0007894a12e ]

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: CK Hu <ck.hu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231214055847.4936-23-shawn.sung@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_merge.c b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
index e525a6b..22f768d 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_disp_merge.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
@@ -103,7 +103,7 @@ 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);
 }