diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 34791fb..bc2d0ec 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -340,7 +340,7 @@
 			seq_printf(m, "No flip due on pipe %c (plane %c)\n",
 				   pipe, plane);
 		} else {
-			if (!work->pending) {
+			if (atomic_read(&work->pending) < INTEL_FLIP_COMPLETE) {
 				seq_printf(m, "Flip queued on pipe %c (plane %c)\n",
 					   pipe, plane);
 			} else {
@@ -351,7 +351,7 @@
 				seq_printf(m, "Stall check enabled, ");
 			else
 				seq_printf(m, "Stall check waiting for page flip ioctl, ");
-			seq_printf(m, "%d prepares\n", work->pending);
+			seq_printf(m, "%d prepares\n", atomic_read(&work->pending));
 
 			if (work->old_fb_obj) {
 				struct drm_i915_gem_object *obj = work->old_fb_obj;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 8bca2d2..fc6f32a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1251,7 +1251,9 @@
 	spin_lock_irqsave(&dev->event_lock, flags);
 	work = intel_crtc->unpin_work;
 
-	if (work == NULL || work->pending || !work->enable_stall_check) {
+	if (work == NULL ||
+	    atomic_read(&work->pending) >= INTEL_FLIP_COMPLETE ||
+	    !work->enable_stall_check) {
 		/* Either the pending flip IRQ arrived, or we're too early. Don't check */
 		spin_unlock_irqrestore(&dev->event_lock, flags);
 		return;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 6b6cf17..38f5bb1 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7245,11 +7245,18 @@
 
 	spin_lock_irqsave(&dev->event_lock, flags);
 	work = intel_crtc->unpin_work;
-	if (work == NULL || !work->pending) {
+
+	/* Ensure we don't miss a work->pending update ... */
+	smp_rmb();
+
+	if (work == NULL || atomic_read(&work->pending) < INTEL_FLIP_COMPLETE) {
 		spin_unlock_irqrestore(&dev->event_lock, flags);
 		return;
 	}
 
+	/* and that the unpin work is consistent wrt ->pending. */
+	smp_rmb();
+
 	intel_crtc->unpin_work = NULL;
 
 	if (work->event) {
@@ -7321,16 +7328,25 @@
 		to_intel_crtc(dev_priv->plane_to_crtc_mapping[plane]);
 	unsigned long flags;
 
+	/* NB: An MMIO update of the plane base pointer will also
+	 * generate a page-flip completion irq, i.e. every modeset
+	 * is also accompanied by a spurious intel_prepare_page_flip().
+	 */
 	spin_lock_irqsave(&dev->event_lock, flags);
-	if (intel_crtc->unpin_work) {
-		if ((++intel_crtc->unpin_work->pending) > 1)
-			DRM_ERROR("Prepared flip multiple times\n");
-	} else {
-		DRM_DEBUG_DRIVER("preparing flip with no unpin work?\n");
-	}
+	if (intel_crtc->unpin_work)
+		atomic_inc_not_zero(&intel_crtc->unpin_work->pending);
 	spin_unlock_irqrestore(&dev->event_lock, flags);
 }
 
+inline static void intel_mark_page_flip_active(struct intel_crtc *intel_crtc)
+{
+	/* Ensure that the work item is consistent when activating it ... */
+	smp_wmb();
+	atomic_set(&intel_crtc->unpin_work->pending, INTEL_FLIP_PENDING);
+	/* and that it is marked active as soon as the irq could fire. */
+	smp_wmb();
+}
+
 static int intel_gen2_queue_flip(struct drm_device *dev,
 				 struct drm_crtc *crtc,
 				 struct drm_framebuffer *fb,
@@ -7367,6 +7383,8 @@
 	OUT_RING(fb->pitches[0]);
 	OUT_RING(obj->gtt_offset + offset);
 	OUT_RING(0); /* aux display base address, unused */
+
+	intel_mark_page_flip_active(intel_crtc);
 	ADVANCE_LP_RING();
 	return 0;
 
@@ -7410,6 +7428,7 @@
 	OUT_RING(obj->gtt_offset + offset);
 	OUT_RING(MI_NOOP);
 
+	intel_mark_page_flip_active(intel_crtc);
 	ADVANCE_LP_RING();
 	return 0;
 
@@ -7453,6 +7472,8 @@
 	pf = 0;
 	pipesrc = I915_READ(PIPESRC(intel_crtc->pipe)) & 0x0fff0fff;
 	OUT_RING(pf | pipesrc);
+
+	intel_mark_page_flip_active(intel_crtc);
 	ADVANCE_LP_RING();
 	return 0;
 
@@ -7494,6 +7515,8 @@
 	pf = 0;
 	pipesrc = I915_READ(PIPESRC(intel_crtc->pipe)) & 0x0fff0fff;
 	OUT_RING(pf | pipesrc);
+
+	intel_mark_page_flip_active(intel_crtc);
 	ADVANCE_LP_RING();
 	return 0;
 
@@ -7548,6 +7571,8 @@
 	intel_ring_emit(ring, (fb->pitches[0] | obj->tiling_mode));
 	intel_ring_emit(ring, (obj->gtt_offset));
 	intel_ring_emit(ring, (MI_NOOP));
+
+	intel_mark_page_flip_active(intel_crtc);
 	intel_ring_advance(ring);
 	return 0;
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index cd623e8..018dfbd 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -277,7 +277,10 @@
 	struct drm_i915_gem_object *old_fb_obj;
 	struct drm_i915_gem_object *pending_flip_obj;
 	struct drm_pending_vblank_event *event;
-	int pending;
+	atomic_t pending;
+#define INTEL_FLIP_INACTIVE	0
+#define INTEL_FLIP_PENDING	1
+#define INTEL_FLIP_COMPLETE	2
 	bool enable_stall_check;
 };