[PATCH 22/24] drm/amd/display: Handle Y carry-over in VCP X.Y calculation

[Anson Jacob]

From: George Shen <george.shen at amd.com>

[Why/How]
Theoretically rare corner case where ceil(Y) results in rounding
up to an integer. If this happens, the 1 should be carried over to
the X value.

Reviewed-by: Wenjing Liu <wenjing.liu at amd.com>
Acked-by: Anson Jacob <Anson.Jacob at amd.com>
Signed-off-by: George Shen <george.shen at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
index 687c3c6881a9..b0c08ee6bc2c 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
@@ -647,6 +647,12 @@ void enc1_stream_encoder_set_throttled_vcp_size(
 				x),
 			26));
 
+	// If y rounds up to integer, carry it over to x.
+	if (y >> 26) {
+		x += 1;
+		y = 0;
+	}
+
 	REG_SET_2(DP_MSE_RATE_CNTL, 0,
 		DP_MSE_RATE_X, x,
 		DP_MSE_RATE_Y, y);
-- 
2.25.1