For some greater resolution, the rdma threshold
variable will overflow.

Signed-off-by: Bibby Hsieh <redacted>
---
 drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
index 0df05f9..8540aaa 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c

@@ -109,7 +109,7 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
 			    unsigned int height, unsigned int vrefresh,
 			    unsigned int bpc)
 {
-	unsigned int threshold;
+	unsigned long long threshold;
 	unsigned int reg;
 
 	rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_0, 0xfff, width);

@@ -121,10 +121,11 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
 	 * output threshold to 6 microseconds with 7/6 overhead to
 	 * account for blanking, and with a pixel depth of 4 bytes:
 	 */
-	threshold = width * height * vrefresh * 4 * 7 / 1000000;
+	threshold = div_u64((unsigned long long)width * height * vrefresh *
+			    4 * 7, 1000000);
 	reg = RDMA_FIFO_UNDERFLOW_EN |
 	      RDMA_FIFO_PSEUDO_SIZE(SZ_8K) |
-	      RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);
+	      RDMA_OUTPUT_VALID_FIFO_THRESHOLD(clamp_val(threshold, 0, 0x3ff0));