drm/nv50/fifo: prevent races between clients updating playlists

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/core/engine/fifo/nv50.c b/drivers/gpu/drm/nouveau/core/engine/fifo/nv50.c
index ddaeb55..89bf459 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/engine/fifo/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/engine/fifo/nv50.c
@@ -47,6 +47,7 @@ nv50_fifo_playlist_update(struct nv50_fifo_priv *priv)
        struct nouveau_gpuobj *cur;
        int i, p;
 
+       mutex_lock(&nv_subdev(priv)->mutex);
        cur = priv->playlist[priv->cur_playlist];
        priv->cur_playlist = !priv->cur_playlist;
 
@@ -60,6 +61,7 @@ nv50_fifo_playlist_update(struct nv50_fifo_priv *priv)
        nv_wr32(priv, 0x0032f4, cur->addr >> 12);
        nv_wr32(priv, 0x0032ec, p);
        nv_wr32(priv, 0x002500, 0x00000101);
+       mutex_unlock(&nv_subdev(priv)->mutex);
 }
 
 static int