From: Nikola Cornij <nikola.cornij@amd.com>
Date: Fri, 27 Apr 2018 17:26:25 -0400
Subject: drm/amd/display: Clear underflow status for debug purposes
Git-commit: a944744ba517256fcc9311e12c083563cbbe7c88
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

We want to keep underflow sticky bit on for the longevity tests outside
of test environment. For debug purposes it is, however, useful to clear
underflow status after the test that caused it so that the following
tests are not affected. This change fullfils both requirements by clearing
the underflow only from within Windows or Diags test environment.

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Nikola Cornij <Nikola.Cornij@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -326,6 +326,12 @@ void dcn10_log_hw_state(struct dc *dc)
 				s.h_total,
 				s.v_total,
 				s.underflow_occurred_status);
+
+		// Clear underflow for debug purposes
+		// We want to keep underflow sticky bit on for the longevity tests outside of test environment.
+		// This function is called only from Windows or Diags test environment, hence it's safe to clear
+		// it from here without affecting the original intent.
+		tg->funcs->clear_optc_underflow(tg);
 	}
 	DTN_INFO("\n");