drm/nvc0/fence: restore pre-suspend fence buffer context on resume

Fixes some unfortunate races on resume.  The G84 version of the code doesn't
need this as "gpuobj"s are automagically suspended/resumed by the core code
whereas pinned buffer objects are not.

Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nvc0_fence.c b/drivers/gpu/drm/nouveau/nvc0_fence.c
index 47ab388a606e..8e5a2f407ed4 100644
--- a/drivers/gpu/drm/nouveau/nvc0_fence.c
+++ b/drivers/gpu/drm/nouveau/nvc0_fence.c
@@ -32,6 +32,7 @@
 struct nvc0_fence_priv {
         struct nouveau_fence_priv base;
         struct nouveau_bo *bo;
+        u32 *suspend;
 };
 
 struct nvc0_fence_chan {
@@ -125,12 +126,36 @@ nvc0_fence_context_new(struct nouveau_channel *chan, int engine)
 static int
 nvc0_fence_fini(struct drm_device *dev, int engine, bool suspend)
 {
+        struct nouveau_fifo_priv *pfifo = nv_engine(dev, NVOBJ_ENGINE_FIFO);
+        struct nvc0_fence_priv *priv = nv_engine(dev, engine);
+        int i;
+
+        if (suspend) {
+                priv->suspend = vmalloc(pfifo->channels * sizeof(u32));
+                if (!priv->suspend)
+                        return -ENOMEM;
+
+                for (i = 0; i < pfifo->channels; i++)
+                        priv->suspend[i] = nouveau_bo_rd32(priv->bo, i);
+        }
+
         return 0;
 }
 
 static int
 nvc0_fence_init(struct drm_device *dev, int engine)
 {
+        struct nouveau_fifo_priv *pfifo = nv_engine(dev, NVOBJ_ENGINE_FIFO);
+        struct nvc0_fence_priv *priv = nv_engine(dev, engine);
+        int i;
+
+        if (priv->suspend) {
+                for (i = 0; i < pfifo->channels; i++)
+                        nouveau_bo_wr32(priv->bo, i, priv->suspend[i]);
+                vfree(priv->suspend);
+                priv->suspend = NULL;
+        }
+
         return 0;
 }