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 <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 7a710a8bc909313951eb9252d8419924c771d7c2 Mon Sep 17 00:00:00 2001 From: Imre Deak <imre.deak@xxxxxxxxx> 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(). Cc: Lyude Paul <lyude@xxxxxxxxxx> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5292 Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v5.14+ Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20220614094537.885472-1-imre.deak@xxxxxxxxx diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 9aa2c20904e3..93651bc9a02c 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -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; }
