FAILED: patch "[PATCH] drm/amd/display: Send DP_TOTAL_LTTPR_CNT during detection if" failed to apply to 4.19-stable tree

FAILED: patch "[PATCH] drm/amd/display: Send DP_TOTAL_LTTPR_CNT during detection if" failed to apply to 4.19-stable tree

[gregkh]

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 d03415f60b3401914fabd27a20017f8056fd5e40
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024081227-unfilled-embark-efe9@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

d03415f60b34 ("drm/amd/display: Send DP_TOTAL_LTTPR_CNT during detection if LTTPR is present")
bc33f5e5f05b ("drm/amd/display: create accessories, hwss and protocols sub folders in link")
028c4ccfb812 ("drm/amd/display: force connector state when bpc changes during compliance")
603a521ec279 ("drm/amd/display: remove duplicate included header files")
d5a43956b73b ("drm/amd/display: move dp capability related logic to link_dp_capability")
94dfeaa46925 ("drm/amd/display: move dp phy related logic to link_dp_phy")
630168a97314 ("drm/amd/display: move dp link training logic to link_dp_training")
d144b40a4833 ("drm/amd/display: move dc_link_dpia logic to link_dp_dpia")
a28d0bac0956 ("drm/amd/display: move dpcd logic from dc_link_dpcd to link_dpcd")
a98cdd8c4856 ("drm/amd/display: refactor ddc logic from dc_link_ddc to link_ddc")
4370f72e3845 ("drm/amd/display: refactor hpd logic from dc_link to link_hpd")
0e8cf83a2b47 ("drm/amd/display: allow hpo and dio encoder switching during dp retrain test")
7462475e3a06 ("drm/amd/display: move dccg programming from link hwss hpo dp to hwss")
e85d59885409 ("drm/amd/display: use encoder type independent hwss instead of accessing enc directly")
ebf13b72020a ("drm/amd/display: Revert Scaler HCBlank issue workaround")
639f6ad6df7f ("drm/amd/display: Revert Reduce delay when sink device not able to ACK 00340h write")
e3aa827e2ab3 ("drm/amd/display: Avoid setting pixel rate divider to N/A")
fe4e2662b2dd ("drm/amd/display: Phase 1 Add Bw Allocation source and header files")
180f33d27a55 ("drm/amd/display: Adjust DP 8b10b LT exit behavior")
b7ada7ee61d3 ("drm/amd/display: Populate DP2.0 output type for DML pipe")

thanks,

greg k-h

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

From d03415f60b3401914fabd27a20017f8056fd5e40 Mon Sep 17 00:00:00 2001
From: Michael Strauss <michael.strauss@amd.com>
Date: Tue, 28 Nov 2023 10:31:12 -0500
Subject: [PATCH] drm/amd/display: Send DP_TOTAL_LTTPR_CNT during detection if
 LTTPR is present

[WHY]
New register field added in DP2.1 SCR, needed for auxless ALPM

[HOW]
Echo value read from 0xF0007 back to sink

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@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_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index 00974c50e11f..f1cac74dd7f7 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -1605,9 +1605,17 @@ static bool retrieve_link_cap(struct dc_link *link)
 			return false;
 	}
 
-	if (dp_is_lttpr_present(link))
+	if (dp_is_lttpr_present(link)) {
 		configure_lttpr_mode_transparent(link);
 
+		// Echo TOTAL_LTTPR_CNT back downstream
+		core_link_write_dpcd(
+				link,
+				DP_TOTAL_LTTPR_CNT,
+				&link->dpcd_caps.lttpr_caps.phy_repeater_cnt,
+				sizeof(link->dpcd_caps.lttpr_caps.phy_repeater_cnt));
+	}
+
 	/* Read DP tunneling information. */
 	status = dpcd_get_tunneling_device_data(link);
 
diff --git a/drivers/gpu/drm/amd/display/include/dpcd_defs.h b/drivers/gpu/drm/amd/display/include/dpcd_defs.h
index 914f28e9f224..aee5170f5fb2 100644
--- a/drivers/gpu/drm/amd/display/include/dpcd_defs.h
+++ b/drivers/gpu/drm/amd/display/include/dpcd_defs.h
@@ -177,4 +177,9 @@ enum dpcd_psr_sink_states {
 #define DP_SINK_PR_PIXEL_DEVIATION_PER_LINE     0x379
 #define DP_SINK_PR_MAX_NUMBER_OF_DEVIATION_LINE 0x37A
 
+/* Remove once drm_dp_helper.h is updated upstream */
+#ifndef DP_TOTAL_LTTPR_CNT
+#define DP_TOTAL_LTTPR_CNT                                  0xF000A /* 2.1 */
+#endif
+
 #endif /* __DAL_DPCD_DEFS_H__ */