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Commit cd961bb9 authored by Daniel Vetter's avatar Daniel Vetter Committed by Dave Airlie
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drm/mst: fix recursive sleep warning on qlock 



With drm-next, we can get a backtrace from sleeping
with mutex detection.

this is due to the callback checking the txmsg state taking
the mutex, which can cause a sleep inside a sleep,

Daniel went over it and was happy we could drop this mutex
in this case.

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 9a6f5130

drivers/gpu/drm/drm_dp_mst_topology.c

+8 −3
Original line number Diff line number Diff line
@@ -733,10 +733,14 @@ static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr, 
			      struct drm_dp_sideband_msg_tx *txmsg)

{

	bool ret;

	mutex_lock(&mgr->qlock);



	/*

	 * All updates to txmsg->state are protected by mgr->qlock, and the two

	 * cases we check here are terminal states. For those the barriers

	 * provided by the wake_up/wait_event pair are enough.

	 */

	ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX ||

	       txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT);

	mutex_unlock(&mgr->qlock);

	return ret;

}
@@ -1363,12 +1367,13 @@ static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr, 
	return 0;

}



/* must be called holding qlock */

static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)

{

	struct drm_dp_sideband_msg_tx *txmsg;

	int ret;



	WARN_ON(!mutex_is_locked(&mgr->qlock));



	/* construct a chunk from the first msg in the tx_msg queue */

	if (list_empty(&mgr->tx_msg_downq)) {

		mgr->tx_down_in_progress = false;