[PATCH 5.3 009/166] drm/amd/display: Clear FEC_READY shadow register if DPCD write fails

[Greg Kroah-Hartman]

From: Nikola Cornij <nikola.cornij@xxxxxxx>

[ 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@xxxxxxx>
Reviewed-by: Joshua Aberback <Joshua.Aberback@xxxxxxx>
Acked-by: Chris Park <Chris.Park@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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