Merge tag 'drm-misc-fixes-2017-07-20' of git://anongit.freedesktop.org/git/drm-misc into drm-fixes

Core Changes:
- fence: Introduce new fence flag to signify timestamp is populated (Chris)
- mst: Avoid processing incomplete data + fix NULL dereference (Imre)

Driver Changes:
- vc4: Avoid WARN from grabbing a ref from vblank that's not on (Boris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Imre Deak <imre.deak@intel.com>

* tag 'drm-misc-fixes-2017-07-20' of git://anongit.freedesktop.org/git/drm-misc:
  drm/mst: Avoid processing partially received up/down message transactions
  drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req()
  drm/mst: Fix error handling during MST sideband message reception
  drm/vc4: Fix VBLANK handling in crtc->enable() path
  dma-buf/fence: Avoid use of uninitialised timestamp

drivers/dma-buf/dma-fence.c

@@ -75,11 +75,6 @@ int dma_fence_signal_locked(struct dma_fence *fence)
 	if (WARN_ON(!fence))
 		return -EINVAL;
 
-	if (!ktime_to_ns(fence->timestamp)) {
-		fence->timestamp = ktime_get();
-		smp_mb__before_atomic();
-	}
-
 	if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
 		ret = -EINVAL;
 
@@ -87,8 +82,11 @@ int dma_fence_signal_locked(struct dma_fence *fence)
 		 * we might have raced with the unlocked dma_fence_signal,
 		 * still run through all callbacks
 		 */
-	} else
+	} else {
+		fence->timestamp = ktime_get();
+		set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
 		trace_dma_fence_signaled(fence);
+	}
 
 	list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
 		list_del_init(&cur->node);
@@ -115,14 +113,11 @@ int dma_fence_signal(struct dma_fence *fence)
 	if (!fence)
 		return -EINVAL;
 
-	if (!ktime_to_ns(fence->timestamp)) {
-		fence->timestamp = ktime_get();
-		smp_mb__before_atomic();
-	}
-
 	if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
 		return -EINVAL;
 
+	fence->timestamp = ktime_get();
+	set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
 	trace_dma_fence_signaled(fence);
 
 	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) {

drivers/dma-buf/sync_debug.c

@@ -84,7 +84,7 @@ static void sync_print_fence(struct seq_file *s,
 		   show ? "_" : "",
 		   sync_status_str(status));
 
-	if (status) {
+	if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) {
 		struct timespec64 ts64 =
 			ktime_to_timespec64(fence->timestamp);
 

drivers/dma-buf/sync_file.c

@@ -391,7 +391,13 @@ static void sync_fill_fence_info(struct dma_fence *fence,
 		sizeof(info->driver_name));
 
 	info->status = dma_fence_get_status(fence);
-	info->timestamp_ns = ktime_to_ns(fence->timestamp);
+	while (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) &&
+	       !test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags))
+		cpu_relax();
+	info->timestamp_ns =
+		test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ?
+		ktime_to_ns(fence->timestamp) :
+		ktime_set(0, 0);
 }
 
 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,

drivers/gpu/drm/drm_dp_mst_topology.c

@@ -330,6 +330,13 @@ static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
 			return false;
 		}
 
+		/*
+		 * ignore out-of-order messages or messages that are part of a
+		 * failed transaction
+		 */
+		if (!recv_hdr.somt && !msg->have_somt)
+			return false;
+
 		/* get length contained in this portion */
 		msg->curchunk_len = recv_hdr.msg_len;
 		msg->curchunk_hdrlen = hdrlen;
@@ -2164,7 +2171,7 @@ out_unlock:
 }
 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
 
-static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
+static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
 {
 	int len;
 	u8 replyblock[32];
@@ -2179,12 +2186,12 @@ static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
 			       replyblock, len);
 	if (ret != len) {
 		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
-		return;
+		return false;
 	}
 	ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
 	if (!ret) {
 		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
-		return;
+		return false;
 	}
 	replylen = msg->curchunk_len + msg->curchunk_hdrlen;
 
@@ -2196,21 +2203,32 @@ static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
 		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
 				    replyblock, len);
 		if (ret != len) {
-			DRM_DEBUG_KMS("failed to read a chunk\n");
+			DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
+				      len, ret);
+			return false;
 		}
+
 		ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
-		if (ret == false)
+		if (!ret) {
 			DRM_DEBUG_KMS("failed to build sideband msg\n");
+			return false;
+		}
+
 		curreply += len;
 		replylen -= len;
 	}
+	return true;
 }
 
 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 {
 	int ret = 0;
 
-	drm_dp_get_one_sb_msg(mgr, false);
+	if (!drm_dp_get_one_sb_msg(mgr, false)) {
+		memset(&mgr->down_rep_recv, 0,
+		       sizeof(struct drm_dp_sideband_msg_rx));
+		return 0;
+	}
 
 	if (mgr->down_rep_recv.have_eomt) {
 		struct drm_dp_sideband_msg_tx *txmsg;
@@ -2266,7 +2284,12 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
 {
 	int ret = 0;
-	drm_dp_get_one_sb_msg(mgr, true);
+
+	if (!drm_dp_get_one_sb_msg(mgr, true)) {
+		memset(&mgr->up_req_recv, 0,
+		       sizeof(struct drm_dp_sideband_msg_rx));
+		return 0;
+	}
 
 	if (mgr->up_req_recv.have_eomt) {
 		struct drm_dp_sideband_msg_req_body msg;
@@ -2318,7 +2341,9 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
 			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
 		}
 
-		drm_dp_put_mst_branch_device(mstb);
+		if (mstb)
+			drm_dp_put_mst_branch_device(mstb);
+
 		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
 	}
 	return ret;

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -520,6 +520,34 @@ static void vc4_crtc_disable(struct drm_crtc *crtc)
 		     SCALER_DISPSTATX_EMPTY);
 }
 
+static void vc4_crtc_update_dlist(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
+	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
+
+	if (crtc->state->event) {
+		unsigned long flags;
+
+		crtc->state->event->pipe = drm_crtc_index(crtc);
+
+		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
+
+		spin_lock_irqsave(&dev->event_lock, flags);
+		vc4_crtc->event = crtc->state->event;
+		crtc->state->event = NULL;
+
+		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
+			  vc4_state->mm.start);
+
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+	} else {
+		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
+			  vc4_state->mm.start);
+	}
+}
+
 static void vc4_crtc_enable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
@@ -530,6 +558,12 @@ static void vc4_crtc_enable(struct drm_crtc *crtc)
 
 	require_hvs_enabled(dev);
 
+	/* Enable vblank irq handling before crtc is started otherwise
+	 * drm_crtc_get_vblank() fails in vc4_crtc_update_dlist().
+	 */
+	drm_crtc_vblank_on(crtc);
+	vc4_crtc_update_dlist(crtc);
+
 	/* Turn on the scaler, which will wait for vstart to start
 	 * compositing.
 	 */
@@ -541,9 +575,6 @@ static void vc4_crtc_enable(struct drm_crtc *crtc)
 	/* Turn on the pixel valve, which will emit the vstart signal. */
 	CRTC_WRITE(PV_V_CONTROL,
 		   CRTC_READ(PV_V_CONTROL) | PV_VCONTROL_VIDEN);
-
-	/* Enable vblank irq handling after crtc is started. */
-	drm_crtc_vblank_on(crtc);
 }
 
 static bool vc4_crtc_mode_fixup(struct drm_crtc *crtc,
@@ -598,7 +629,6 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
 {
 	struct drm_device *dev = crtc->dev;
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
-	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
 	struct drm_plane *plane;
 	bool debug_dump_regs = false;
@@ -620,25 +650,15 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
 
 	WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm.size);
 
-	if (crtc->state->event) {
+	/* Only update DISPLIST if the CRTC was already running and is not
-		unsigned long flags;
+	 * being disabled.
-
+	 * vc4_crtc_enable() takes care of updating the dlist just after
-		crtc->state->event->pipe = drm_crtc_index(crtc);
+	 * re-enabling VBLANK interrupts and before enabling the engine.
-
+	 * If the CRTC is being disabled, there's no point in updating this
-		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
+	 * information.
-
+	 */
-		spin_lock_irqsave(&dev->event_lock, flags);
+	if (crtc->state->active && old_state->active)
-		vc4_crtc->event = crtc->state->event;
+		vc4_crtc_update_dlist(crtc);
-		crtc->state->event = NULL;
-
-		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
-			  vc4_state->mm.start);
-
-		spin_unlock_irqrestore(&dev->event_lock, flags);
-	} else {
-		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
-			  vc4_state->mm.start);
-	}
 
 	if (debug_dump_regs) {
 		DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc));

include/linux/dma-fence.h

@@ -55,6 +55,7 @@ struct dma_fence_cb;
  * of the time.
  *
  * DMA_FENCE_FLAG_SIGNALED_BIT - fence is already signaled
+ * DMA_FENCE_FLAG_TIMESTAMP_BIT - timestamp recorded for fence signaling
  * DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT - enable_signaling might have been called
  * DMA_FENCE_FLAG_USER_BITS - start of the unused bits, can be used by the
  * implementer of the fence for its own purposes. Can be used in different
@@ -84,6 +85,7 @@ struct dma_fence {
 
 enum dma_fence_flag_bits {
 	DMA_FENCE_FLAG_SIGNALED_BIT,
+	DMA_FENCE_FLAG_TIMESTAMP_BIT,
 	DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
 	DMA_FENCE_FLAG_USER_BITS, /* must always be last member */
 };