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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Qingqing Zhuo <qingqing.zhuo@amd.com>,
        Hersen Wu <hersenxs.wu@amd.com>,
        Aurabindo Pillai <aurabindo.pillai@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 33/98] drm/amd/display: workaround for hard hang on HPD on native DP
Date:   Tue, 24 Aug 2021 12:58:03 -0400
Message-Id: <20210824165908.709932-34-sashal@kernel.org>
In-Reply-To: <20210824165908.709932-1-sashal@kernel.org>
References: <20210824165908.709932-1-sashal@kernel.org>
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From: Qingqing Zhuo <qingqing.zhuo@amd.com>

[ Upstream commit c4152b297d56d3696ad0a9003169bc5b98ad7b72 ]

[Why]
HPD disable and enable sequences are not mutually exclusive
on Linux. For HPDs that spans over 1s (i.e. HPD low = 1s),
part of the disable sequence (specifically, a request to SMU
to lower refclk) could come right before the call to PHY
enable, causing DMUB to access an unresponsive PHY
and thus a hard hang on the system.

[How]
Disable 48mhz refclk off on native DP.

Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
index 1c6e401dd4cc..0eba391e597f 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
@@ -66,9 +66,11 @@ int rn_get_active_display_cnt_wa(
 	for (i = 0; i < context->stream_count; i++) {
 		const struct dc_stream_state *stream = context->streams[i];
 
+		/* Extend the WA to DP for Linux*/
 		if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A ||
 				stream->signal == SIGNAL_TYPE_DVI_SINGLE_LINK ||
-				stream->signal == SIGNAL_TYPE_DVI_DUAL_LINK)
+				stream->signal == SIGNAL_TYPE_DVI_DUAL_LINK ||
+				stream->signal == SIGNAL_TYPE_DISPLAY_PORT)
 			tmds_present = true;
 	}
 
-- 
2.30.2