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authorLyude <cpaul@redhat.com>2016-04-13 16:50:18 -0400
committerDave Airlie <airlied@redhat.com>2016-04-27 09:29:40 +1000
commit9dc0487d96a0396367a1451b31873482080b527f (patch)
treedc083818cc8043589069ae0ec9bb5bc9285ff38a /drivers/gpu
parent263efde31f97c498e1ebad30e4d2906609d7ad6b (diff)
downloadlinux-9dc0487d96a0396367a1451b31873482080b527f.tar.bz2
drm/dp/mst: Restore primary hub guid on resume
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> Reviewed-by: Harry Wentland <harry.wentland@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> 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 <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/drm_dp_mst_topology.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 935d8cc46841..71ea0521ea96 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2136,6 +2136,8 @@ 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");
@@ -2150,6 +2152,16 @@ 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;