drm/amd/display: Handle Y carry-over in VCP X.Y calculation

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.

CC: [email protected]
Reviewed-by: Rodrigo Siqueira <[email protected]>
Signed-off-by: George Shen <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: George Shen

drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c

@@ -395,6 +395,12 @@ void dcn31_hpo_dp_link_enc_set_throttled_vcp_size(
 				x),
 			25));
 
+	// If y rounds up to integer, carry it over to x.
+	if (y >> 25) {
+		x += 1;
+		y = 0;
+	}
+
 	switch (stream_encoder_inst) {
 	case 0:
 		REG_SET_2(DP_DPHY_SYM32_VC_RATE_CNTL0, 0,