From: Ilya Bakoulin <ilya.bakoulin@amd.com>
Date: Wed, 17 Apr 2024 18:21:28 +0000 (-0400)
Subject: drm/amd/display: Fix FEC_READY write on DP LT
X-Git-Tag: v6.11-rc1~141^2~25^2~530
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a8baec4623aedf36d50767627f6eae5ebf07c6fb;p=thirdparty%2Fkernel%2Flinux.git

drm/amd/display: Fix FEC_READY write on DP LT

[Why/How]
We can miss writing FEC_READY in some cases before LT start, which
violates DP spec. Remove the condition guarding the DPCD write so that
the write happens unconditionally.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c
index 5cbf5f93e584f..bafa52a0165a0 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c
@@ -151,16 +151,14 @@ enum dc_status dp_set_fec_ready(struct dc_link *link, const struct link_resource
 		return DC_NOT_SUPPORTED;
 
 	if (ready && dp_should_enable_fec(link)) {
-		if (link->fec_state == dc_link_fec_not_ready) {
-			fec_config = 1;
+		fec_config = 1;
 
-			status = core_link_write_dpcd(link, DP_FEC_CONFIGURATION,
-					&fec_config, sizeof(fec_config));
+		status = core_link_write_dpcd(link, DP_FEC_CONFIGURATION,
+				&fec_config, sizeof(fec_config));
 
-			if (status == DC_OK) {
-				link_enc->funcs->fec_set_ready(link_enc, true);
-				link->fec_state = dc_link_fec_ready;
-			}
+		if (status == DC_OK) {
+			link_enc->funcs->fec_set_ready(link_enc, true);
+			link->fec_state = dc_link_fec_ready;
 		}
 	} else {
 		if (link->fec_state == dc_link_fec_ready) {