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authorLyude Paul <lyude@redhat.com>2019-06-17 19:57:33 -0400
committerLyude Paul <lyude@redhat.com>2019-10-24 14:29:48 -0400
commit6f85f73821f6af4de4429ab2f2f7958dbd81cb90 (patch)
treeacbc224a28dc677e2dbbf583e3c3fa736fc4c1c6 /include/drm
parentd20ebea8f0fabaac0048c7102a6befe37c2bb9c4 (diff)
downloadlinux-6f85f73821f6af4de4429ab2f2f7958dbd81cb90.tar.bz2
drm/dp_mst: Add basic topology reprobing when resuming
Finally! For a very long time, our MST helpers have had one very annoying issue: They don't know how to reprobe the topology state when coming out of suspend. This means that if a user has a machine connected to an MST topology and decides to suspend their machine, we lose all topology changes that happened during that period. That can be a big problem if the machine was connected to a different topology on the same port before resuming, as we won't bother reprobing any of the ports and likely cause the user's monitors not to come back up as expected. So, we start fixing this by teaching our MST helpers how to reprobe the link addresses of each connected topology when resuming. As it turns out, the behavior that we want here is identical to the behavior we want when initially probing a newly connected MST topology, with a couple of important differences: - We need to be more careful about handling the potential races between events from the MST hub that could change the topology state as we're performing the link address reprobe - We need to be more careful about handling unlikely state changes on ports - such as an input port turning into an output port, something that would be far more likely to happen in situations like the MST hub we're connected to being changed while we're suspend Both of which have been solved by previous commits. That leaves one requirement: - We need to prune any MST ports in our in-memory topology state that were present when suspending, but have not appeared in the post-resume link address response from their parent branch device Which we can now handle in this commit by modifying drm_dp_send_link_address(). We then introduce suspend/resume reprobing by introducing drm_dp_mst_topology_mgr_invalidate_mstb(), which we call in drm_dp_mst_topology_mgr_suspend() to traverse the in-memory topology state to indicate that each mstb needs it's link address resent and PBN resources reprobed. On resume, we start back up &mgr->work and have it reprobe the topology in the same way we would on a hotplug, removing any leftover ports that no longer appear in the topology state. Changes since v4: * Split indenting changes in drm_dp_mst_topology_mgr_resume() into a separate patch * Only fire hotplugs when something has actually changed after a link address probe * Don't try to change port->connector at all on ports, just throw out ports that need their connectors removed to make things easier. Cc: Juston Li <juston.li@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Harry Wentland <hwentlan@amd.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Sean Paul <sean@poorly.run> Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191022023641.8026-14-lyude@redhat.com
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/drm_dp_mst_helper.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index fd142db42cb0..144027e27464 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -706,7 +706,8 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
int __must_check
-drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
+drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
+ bool sync);
ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
unsigned int offset, void *buffer, size_t size);