All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] drm/dp/mst: Restore primary hub guid on resume
@ 2016-04-13 20:50 ` Lyude
  0 siblings, 0 replies; 4+ messages in thread
From: Lyude @ 2016-04-13 20:50 UTC (permalink / raw)
  To: dri-devel; +Cc: Lyude, David Airlie, open list

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 <cpaul@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 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 27fbd79..d2efd78 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2121,6 +2121,8 @@ 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");
@@ -2135,6 +2137,16 @@ 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;
-- 
2.5.5

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2016-04-15 13:01 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-04-13 20:50 [PATCH] drm/dp/mst: Restore primary hub guid on resume Lyude
2016-04-13 20:50 ` Lyude
2016-04-15 12:41 ` Harry Wentland
2016-04-15 13:01   ` Daniel Vetter

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.