FAILED: patch "[PATCH] drm/amd/display: Fix FEC_READY write on DP LT" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] drm/amd/display: Fix FEC_READY write on DP LT" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x a8baec4623aedf36d50767627f6eae5ebf07c6fb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024081210-collie-staunch-198a@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

a8baec4623ae ("drm/amd/display: Fix FEC_READY write on DP LT")
a8ac994cf069 ("drm/amd/display: Disable error correction if it's not supported")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a8baec4623aedf36d50767627f6eae5ebf07c6fb Mon Sep 17 00:00:00 2001
From: Ilya Bakoulin <ilya.bakoulin@amd.com>
Date: Wed, 17 Apr 2024 14:21:28 -0400
Subject: [PATCH] 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 5cbf5f93e584..bafa52a0165a 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) {