[PATCH 6.18 175/752] drm/amd/display: Disable FEC when powering down encoders

Sasha Levin
2026-02-28T17:50:37Z

From: Ovidiu Bunea <ovidiu.bunea@amd.com>

[ Upstream commit 8cee62904caf95e5698fa0f2d420f5f22b4dea15 ]

[why & how]
VBIOS DMCUB FW can enable FEC for capable eDPs, but S/W DC state is
only updated for link0 when transitioning into OS with driver loaded.
This causes issues when the eDP is immediately hidden and DIG0 is
assigned to another link that does not support FEC. Driver will
attempt to disable FEC but FEC enablement occurs based on the link
state, which does not have fec_state updated since it is a different
link. Thus, FEC disablement on DIG0 will get skipped and cause no
light up.

Reviewed-by: Karen Chen <karen.chen@amd.com>
Signed-off-by: Ovidiu Bunea <ovidiu.bunea@amd.com>
Signed-off-by: Matthew Stewart <matthew.stewart2@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../amd/display/dc/hwss/dce110/dce110_hwseq.c | 24 ++++++++++++-------
1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
index 7e36c063f0da5..65e66bfc4161c 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
@@ -59,6 +59,7 @@
#include "dc_state_priv.h"
#include "dpcd_defs.h"
#include "dsc.h"
+#include "dc_dp_types.h"
/* include DCE11 register header files */
#include "dce/dce_11_0_d.h"
#include "dce/dce_11_0_sh_mask.h"
@@ -1729,20 +1730,25 @@ static void power_down_encoders(struct dc *dc)
int i;

for (i = 0; i < dc->link_count; i++) {
- enum signal_type signal = dc->links[i]->connector_signal;
-
- dc->link_srv->blank_dp_stream(dc->links[i], false);
+ struct dc_link *link = dc->links[i];
+ struct link_encoder *link_enc = link->link_enc;
+ enum signal_type signal = link->connector_signal;

+ dc->link_srv->blank_dp_stream(link, false);
if (signal != SIGNAL_TYPE_EDP)
signal = SIGNAL_TYPE_NONE;

- if (dc->links[i]->ep_type == DISPLAY_ENDPOINT_PHY)
- dc->links[i]->link_enc->funcs->disable_output(
- dc->links[i]->link_enc, signal);
+ if (link->ep_type == DISPLAY_ENDPOINT_PHY)
+ link_enc->funcs->disable_output(link_enc, signal);
+
+ if (link->fec_state == dc_link_fec_enabled) {
+ link_enc->funcs->fec_set_enable(link_enc, false);
+ link_enc->funcs->fec_set_ready(link_enc, false);
+ link->fec_state = dc_link_fec_not_ready;
+ }

- dc->links[i]->link_status.link_active = false;
- memset(&dc->links[i]->cur_link_settings, 0,
- sizeof(dc->links[i]->cur_link_settings));
+ link->link_status.link_active = false;
+ memset(&link->cur_link_settings, 0, sizeof(link->cur_link_settings));
}
}

--
2.51.0