From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:26296 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752750AbcESEUr (ORCPT ); Thu, 19 May 2016 00:20:47 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Lyude , Daniel Vetter , Dave Airlie , Sasha Levin Subject: [added to the 4.1 stable tree] drm/dp/mst: Restore primary hub guid on resume Date: Thu, 19 May 2016 00:19:17 -0400 Message-Id: <1463631606-32540-18-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> References: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: Lyude This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit 9dc0487d96a0396367a1451b31873482080b527f ] Some hubs are forgetful, and end up forgetting whatever GUID we set previously after we do a suspend/resume cycle. This can lead to hotplugging breaking (along with probably other things) since the hub will start sending connection notifications with the wrong GUID. As such, we need to check on resume whether or not the GUID the hub is giving us is valid. Signed-off-by: Lyude Reviewed-by: Harry Wentland Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1460580618-7421-1-git-send-email-cpaul@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_dp_mst_topology.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 23049fb..10b8839 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2122,6 +2122,8 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr) if (mgr->mst_primary) { int sret; + u8 guid[16]; + sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE); if (sret != DP_RECEIVER_CAP_SIZE) { DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n"); @@ -2136,6 +2138,16 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr) ret = -1; goto out_unlock; } + + /* Some hubs forget their guids after they resume */ + sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16); + if (sret != 16) { + DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n"); + ret = -1; + goto out_unlock; + } + drm_dp_check_mstb_guid(mgr->mst_primary, guid); + ret = 0; } else ret = -1; -- 2.5.0