The patch below does not apply to the 4.19-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-4.19.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 '2024081214-bony-overhang-43f4@gregkh' --subject-prefix 'PATCH 4.19.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") 788c6e2ce5c7 ("drm/amd/display: replace all dc_link function call in link with link functions") c69fc3d0de6c ("drm/amd/display: Reduce CPU busy-waiting for long delays") 8e5cfe547bf3 ("drm/amd/display: upstream link_dp_dpia_bw.c") 54618888d1ea ("drm/amd/display: break down dc_link.c") 71d7e8904d54 ("drm/amd/display: Add HDMI manufacturer OUI and device id read") 65a4cfb45e0e ("drm/amdgpu/display: remove duplicate include header in files") e322843e5e33 ("drm/amd/display: fix linux dp link lost handled only one time") 0c2bfcc338eb ("drm/amd/display: Add Function declaration in dc_link") 6ca7415f11af ("drm/amd/display: merge dc_link_dp into dc_link") de3fb390175b ("drm/amd/display: move dp cts functions from dc_link_dp to link_dp_cts") c5a31f178e35 ("drm/amd/display: move dp irq handler functions from dc_link_dp to link_dp_irq_handler") 0078c924e733 ("drm/amd/display: move eDP panel control logic to link_edp_panel_control") bc33f5e5f05b ("drm/amd/display: create accessories, hwss and protocols sub folders in link") 2daeb74b7d66 ("drm/amdgpu/display/mst: update mst_mgr relevant variable when long HPD") 028c4ccfb812 ("drm/amd/display: force connector state when bpc changes during compliance") 603a521ec279 ("drm/amd/display: remove duplicate included header files") bd3149014dff ("drm/amd/display: Decrease messaging about DP alt mode state to debug") d5a43956b73b ("drm/amd/display: move dp capability related logic to link_dp_capability")

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) {