Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux

Pull drm fixes from Dave Airlie:
 "Misc i915, vmwgfx and radeon fixes along with a fix for one of those
  recursive sleep mutex debug cases in the mst code"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/vmwgfx: Fix an issue with the device losing its irq line on module unload
  drm/vmwgfx: Correctly NULLify dma buffer pointer on failure
  drm/vmwgfx: Reorder device takedown somewhat
  drm/vmwgfx: Fix a couple of lock dependency violations
  drm/radeon: drop setting UPLL to sleep mode
  drm/radeon: fix wait to actually occur after the signaling callback
  drm/i915: Prevent TLB error on first execution on SNB
  drm/i915: Do both mt and gen6 style forcewake reset on ivb probe
  drm/i915: Make WAIT_IOCTL negative timeouts be indefinite again
  drm/i915: use in_interrupt() not in_irq() to check context
  drm/mst: fix recursive sleep warning on qlock
  drm: Don't assign fbs for universal cursor support to files

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 9a5b68717ec8..379ab4555756 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -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;