diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
index f985bad61d83..463ed7830d17 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
@@ -83,6 +83,7 @@
 #define GAMMA_MOUT_EN_RDMA1		0x1
 #define RDMA0_SOUT_DPI0			0x2
 #define RDMA0_SOUT_DSI2			0x4
+#define RDMA0_SOUT_DSI3			0x5
 #define RDMA1_SOUT_DPI0			0x2
 #define DPI0_SEL_IN_RDMA1		0x1
 #define COLOR1_SEL_IN_OVL1		0x1
@@ -164,6 +165,9 @@ static unsigned int mtk_ddp_mout_en(enum mtk_ddp_comp_id cur,
 	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DSI2) {
 		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
 		value = RDMA0_SOUT_DSI2;
+	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DSI3) {
+		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
+		value = RDMA0_SOUT_DSI3;
 	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DPI0) {
 		*addr = DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN;
 		value = RDMA1_SOUT_DPI0;