diff --git a/drivers/gpu/drm/rockchip/cdn-dp-reg.c b/drivers/gpu/drm/rockchip/cdn-dp-reg.c
index 3105965fc26034e921de4c86d39475180e70b03c..5a485489a1e23cca8b3c455d368d42320140774e 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-reg.c
+++ b/drivers/gpu/drm/rockchip/cdn-dp-reg.c
@@ -147,7 +147,7 @@ static int cdn_dp_mailbox_validate_receive(struct cdn_dp_device *dp,
 }
 
 static int cdn_dp_mailbox_read_receive(struct cdn_dp_device *dp,
-				       u8 *buff, u8 buff_size)
+				       u8 *buff, u16 buff_size)
 {
 	u32 i;
 	int ret;