linux-kernel - [PATCH AUTOSEL 5.3 11/87] drm/amd/display: Clear FEC_READY shadow register if DPCD write fails

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Date:   Tue, 24 Sep 2019 12:40:27 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Nikola Cornij <nikola.cornij@....com>,
        Joshua Aberback <Joshua.Aberback@....com>,
        Chris Park <Chris.Park@....com>, Leo Li <sunpeng.li@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.3 11/87] drm/amd/display: Clear FEC_READY shadow register if DPCD write fails

From: Nikola Cornij <nikola.cornij@....com>

[ Upstream commit d68a74541735e030dea56f72746cd26d19986f41 ]

[why]
As a fail-safe, in case 'set FEC_READY' DPCD write fails, a HW shadow
register should be cleared and the internal FEC stat should be set to
'not ready'. This is to make sure HW settings will be consistent with
FEC_READY state on the RX.

Signed-off-by: Nikola Cornij <nikola.cornij@....com>
Reviewed-by: Joshua Aberback <Joshua.Aberback@....com>
Acked-by: Chris Park <Chris.Park@....com>
Acked-by: Leo Li <sunpeng.li@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 2c7aaed907b91..0bf85a7a2cd31 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -3033,6 +3033,8 @@ void dp_set_fec_ready(struct dc_link *link, bool ready)
 				link_enc->funcs->fec_set_ready(link_enc, true);
 				link->fec_state = dc_link_fec_ready;
 			} else {
+				link->link_enc->funcs->fec_set_ready(link->link_enc, false);
+				link->fec_state = dc_link_fec_not_ready;
 				dm_error("dpcd write failed to set fec_ready");
 			}
 		} else if (link->fec_state == dc_link_fec_ready && !ready) {
-- 
2.20.1