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authorDave Airlie <airlied@redhat.com>2015-06-15 10:34:28 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-03 09:29:08 -0700
commit5c507167d2ef467ecd2ec4ad40a0bd70b4fad814 (patch)
tree0ab4cf22e1738df9d460447607fed82df3ed4666 /include/drm
parent0f0b7b10c3545704cf0d1705e33f1cc5a9fe8097 (diff)
drm/dp/mst: close deadlock in connector destruction.
commit 6b8eeca65b18ae77e175cc2b6571731f0ee413bf upstream. I've only seen this once, and I failed to capture the lockdep backtrace, but I did some investigations. If we are calling into the MST layer from EDID probing, we have the mode_config mutex held, if during that EDID probing, the MST hub goes away, then we can get a deadlock where the connector destruction function in the driver tries to retake the mode config mutex. This offloads connector destruction to a workqueue, and avoid the subsequenct lock ordering issue. Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/drm_crtc.h2
-rw-r--r--include/drm/drm_dp_mst_helper.h4
2 files changed, 6 insertions, 0 deletions
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index ca71c03143d1..54233583c6cb 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -731,6 +731,8 @@ struct drm_connector {
uint8_t num_h_tile, num_v_tile;
uint8_t tile_h_loc, tile_v_loc;
uint16_t tile_h_size, tile_v_size;
+
+ struct list_head destroy_list;
};
/**
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index a2507817be41..86d0b25ed054 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -463,6 +463,10 @@ struct drm_dp_mst_topology_mgr {
struct work_struct work;
struct work_struct tx_work;
+
+ struct list_head destroy_connector_list;
+ struct mutex destroy_connector_lock;
+ struct work_struct destroy_connector_work;
};
int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, struct device *dev, struct drm_dp_aux *aux, int max_dpcd_transaction_bytes, int max_payloads, int conn_base_id);