linux-kernel - [PATCH 5.11 172/342] drm/amd/display: DCHUB underflow counter increasing in some scenarios

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Message-Id: <20210510102015.795905627@linuxfoundation.org>
Date:   Mon, 10 May 2021 12:19:22 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Daniel Wheeler <daniel.wheeler@....com>,
        Aric Cyr <aric.cyr@....com>,
        Solomon Chiu <solomon.chiu@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.11 172/342] drm/amd/display: DCHUB underflow counter increasing in some scenarios

From: Aric Cyr <aric.cyr@....com>

[ Upstream commit 4710430a779e6077d81218ac768787545bff8c49 ]

[Why]
When unplugging a display, the underflow counter can be seen to
increase because PSTATE switch is allowed even when some planes are not
blanked.

[How]
Check that all planes are not active instead of all streams before
allowing PSTATE change.

Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Aric Cyr <aric.cyr@....com>
Acked-by: Solomon Chiu <solomon.chiu@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
index ab98c259ef69..cbe94cf489c7 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
@@ -252,6 +252,7 @@ static void dcn3_update_clocks(struct clk_mgr *clk_mgr_base,
 	bool force_reset = false;
 	bool update_uclk = false;
 	bool p_state_change_support;
+	int total_plane_count;
 
 	if (dc->work_arounds.skip_clock_update || !clk_mgr->smu_present)
 		return;
@@ -292,7 +293,8 @@ static void dcn3_update_clocks(struct clk_mgr *clk_mgr_base,
 		clk_mgr_base->clks.socclk_khz = new_clocks->socclk_khz;
 
 	clk_mgr_base->clks.prev_p_state_change_support = clk_mgr_base->clks.p_state_change_support;
-	p_state_change_support = new_clocks->p_state_change_support || (display_count == 0);
+	total_plane_count = clk_mgr_helper_get_active_plane_cnt(dc, context);
+	p_state_change_support = new_clocks->p_state_change_support || (total_plane_count == 0);
 	if (should_update_pstate_support(safe_to_lower, p_state_change_support, clk_mgr_base->clks.p_state_change_support)) {
 		clk_mgr_base->clks.p_state_change_support = p_state_change_support;
 
-- 
2.30.2