diff --git a/src/sna/kgem.c b/src/sna/kgem.c
index d27ba78b..a95ce3d1 100644
--- a/src/sna/kgem.c
+++ b/src/sna/kgem.c
@@ -186,6 +186,8 @@ static int gem_read(int fd, uint32_t handle, const void *dst, int length)
 Bool kgem_bo_write(struct kgem *kgem, struct kgem_bo *bo,
 		   const void *data, int length)
 {
+	assert(!gem_busy(kgem->fd, bo->handle));
+
 	if (gem_write(kgem->fd, bo->handle, 0, length, data))
 		return FALSE;
 
@@ -1022,6 +1024,7 @@ void _kgem_submit(struct kgem *kgem)
 		kgem_cleanup(kgem);
 
 	kgem_reset(kgem);
+	kgem->busy = 1;
 }
 
 void kgem_throttle(struct kgem *kgem)
diff --git a/src/sna/kgem.h b/src/sna/kgem.h
index 988281ca..a43a7129 100644
--- a/src/sna/kgem.h
+++ b/src/sna/kgem.h
@@ -105,6 +105,7 @@ struct kgem {
 	uint32_t flush:1;
 	uint32_t need_expire:1;
 	uint32_t need_purge:1;
+	uint32_t busy:1;
 
 	uint32_t has_vmap :1;
 	uint32_t has_relaxed_fencing :1;
diff --git a/src/sna/sna_accel.c b/src/sna/sna_accel.c
index b58cfc80..4f5c1525 100644
--- a/src/sna/sna_accel.c
+++ b/src/sna/sna_accel.c
@@ -4064,13 +4064,15 @@ static bool sna_accel_flush(struct sna *sna)
 	bool nothing_to_do =
 		priv->cpu_damage == NULL && priv->gpu_bo->rq == NULL;
 
-	DBG(("%s (time=%ld), nothing_to_do=%d\n",
-	     __FUNCTION__, (long)GetTimeInMillis(), nothing_to_do));
+	DBG(("%s (time=%ld), nothing_to_do=%d, busy? %d\n",
+	     __FUNCTION__, (long)GetTimeInMillis(),
+	     nothing_to_do, sna->kgem.busy));
 
-	if (nothing_to_do)
+	if (nothing_to_do && !sna->kgem.busy)
 		_sna_accel_disarm_timer(sna, FLUSH_TIMER);
 	else
 		sna_pixmap_move_to_gpu(priv->pixmap);
+	sna->kgem.busy = 0;
 	kgem_bo_flush(&sna->kgem, priv->gpu_bo);
 	return !nothing_to_do;
 }