From: jsg <jsg@openbsd.org>
Date: Mon, 5 Sep 2022 14:15:03 +0000 (+0000)
Subject: drm/amd/display: clear optc underflow before turn off odm clock
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=b7005f21f50eca4c7b06e76a6807ee257d34d5b8;p=openbsd

drm/amd/display: clear optc underflow before turn off odm clock

From Fudong Wang
5ee30bcfdb32526233d2572f3d9ec371928679f1 in linux 5.15.y/5.15.65
b2a93490201300a749ad261b5c5d05cb50179c44 in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_optc.c b/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_optc.c
index 03e8b26b1d7..b9092a7ec2a 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_optc.c
+++ b/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_optc.c
@@ -480,6 +480,11 @@ void optc1_enable_optc_clock(struct timing_generator *optc, bool enable)
 				OTG_CLOCK_ON, 1,
 				1, 1000);
 	} else  {
+
+		//last chance to clear underflow, otherwise, it will always there due to clock is off.
+		if (optc->funcs->is_optc_underflow_occurred(optc) == true)
+			optc->funcs->clear_optc_underflow(optc);
+
 		REG_UPDATE_2(OTG_CLOCK_CONTROL,
 				OTG_CLOCK_GATE_DIS, 0,
 				OTG_CLOCK_EN, 0);