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

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>

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_merge.c b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
index e525a6b9e5b0bc257f6aea8e8dda8e4c47a22899..22f768d923d5ab006a00e7a27b4a799e30094fe9 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);
 }