FAILED: patch "[PATCH] drm/dp/mst: Read the extended DPCD capabilities during system" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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 <[email protected]>.

thanks,

greg k-h

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

From 7a710a8bc909313951eb9252d8419924c771d7c2 Mon Sep 17 00:00:00 2001
From: Imre Deak <[email protected]>
Date: Tue, 14 Jun 2022 12:45:37 +0300
Subject: [PATCH] drm/dp/mst: Read the extended DPCD capabilities during system
resume

The WD22TB4 Thunderbolt dock at least will revert its DP_MAX_LINK_RATE from HBR3 to HBR2 after system suspend/resume if the DP_DP13_DPCD_REV registers are not read subsequently also as required.

Fix this by reading DP_DP13_DPCD_REV registers as well, matching what is done during connector detection. While at it also fix up the same call in drm_dp_mst_dump_topology().

index 9aa2c20904e3..93651bc9a02c 100644
@@ -3860,9 +3860,7 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
 	if (!mgr->mst_primary)
 		goto out_fail;
 
-	ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
-			       DP_RECEIVER_CAP_SIZE);
-	if (ret != DP_RECEIVER_CAP_SIZE) {
+	if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
 		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
 		goto out_fail;
 	}

@@ -4910,8 +4908,7 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
 		u8 buf[DP_PAYLOAD_TABLE_SIZE];
 		int ret;
 
-		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
-		if (ret) {
+		if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
 			seq_printf(m, "dpcd read failed\n");
 			goto out;
 		}