From: jsg <jsg@openbsd.org>
Date: Mon, 20 May 2024 05:24:11 +0000 (+0000)
Subject: drm/amd/display: Handle Y carry-over in VCP X.Y calculation
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=8b4fb3f23334c59c4f05536f3adda5d33b02b83b;p=openbsd

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

From George Shen
7be093e45215d4d9dfda515aebb7c31dc9413144 in linux-6.6.y/6.6.3
719564737a9ac3d0b49c314450b56cf6f7d71358 in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c b/sys/dev/pci/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c
index 083a43c476e..fa8623ccc7e 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c
+++ b/sys/dev/pci/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,