drm/nouveau: fix assumption that semaphore dmaobj is valid in x-chan sync

The DDX modifies DMA_SEMAPHORE on nv50 in order to implement sync-to-vblank,
things will go very wrong for cross-channel sync after this.

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

1 files changed, 25 insertions, 34 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c
index 4b9f4493c9f9..7347075ca5b8 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -339,11 +339,12 @@ semaphore_acquire(struct nouveau_channel *chan, struct nouveau_semaphore *sema)
         int ret;
 
         if (dev_priv->chipset < 0x84) {
-                ret = RING_SPACE(chan, 3);
+                ret = RING_SPACE(chan, 4);
                 if (ret)
                         return ret;
 
-                BEGIN_RING(chan, NvSubSw, NV_SW_SEMAPHORE_OFFSET, 2);
+                BEGIN_RING(chan, NvSubSw, NV_SW_DMA_SEMAPHORE, 3);
+                OUT_RING  (chan, NvSema);
                 OUT_RING  (chan, sema->mem->start);
                 OUT_RING  (chan, 1);
         } else
@@ -351,10 +352,12 @@ semaphore_acquire(struct nouveau_channel *chan, struct nouveau_semaphore *sema)
                 struct nouveau_vma *vma = &dev_priv->fence.bo->vma;
                 u64 offset = vma->offset + sema->mem->start;
 
-                ret = RING_SPACE(chan, 5);
+                ret = RING_SPACE(chan, 7);
                 if (ret)
                         return ret;
 
+                BEGIN_RING(chan, NvSubSw, NV_SW_DMA_SEMAPHORE, 1);
+                OUT_RING  (chan, chan->vram_handle);
                 BEGIN_RING(chan, NvSubSw, 0x0010, 4);
                 OUT_RING  (chan, upper_32_bits(offset));
                 OUT_RING  (chan, lower_32_bits(offset));
@@ -394,11 +397,12 @@ semaphore_release(struct nouveau_channel *chan, struct nouveau_semaphore *sema)
         int ret;
 
         if (dev_priv->chipset < 0x84) {
-                ret = RING_SPACE(chan, 4);
+                ret = RING_SPACE(chan, 5);
                 if (ret)
                         return ret;
 
-                BEGIN_RING(chan, NvSubSw, NV_SW_SEMAPHORE_OFFSET, 1);
+                BEGIN_RING(chan, NvSubSw, NV_SW_DMA_SEMAPHORE, 2);
+                OUT_RING  (chan, NvSema);
                 OUT_RING  (chan, sema->mem->start);
                 BEGIN_RING(chan, NvSubSw, NV_SW_SEMAPHORE_RELEASE, 1);
                 OUT_RING  (chan, 1);
@@ -407,10 +411,12 @@ semaphore_release(struct nouveau_channel *chan, struct nouveau_semaphore *sema)
                 struct nouveau_vma *vma = &dev_priv->fence.bo->vma;
                 u64 offset = vma->offset + sema->mem->start;
 
-                ret = RING_SPACE(chan, 5);
+                ret = RING_SPACE(chan, 7);
                 if (ret)
                         return ret;
 
+                BEGIN_RING(chan, NvSubSw, NV_SW_DMA_SEMAPHORE, 1);
+                OUT_RING  (chan, chan->vram_handle);
                 BEGIN_RING(chan, NvSubSw, 0x0010, 4);
                 OUT_RING  (chan, upper_32_bits(offset));
                 OUT_RING  (chan, lower_32_bits(offset));
@@ -504,22 +510,22 @@ nouveau_fence_channel_init(struct nouveau_channel *chan)
         struct nouveau_gpuobj *obj = NULL;
         int ret;
 
-        if (dev_priv->card_type >= NV_C0)
-                goto out_initialised;
+        if (dev_priv->card_type < NV_C0) {
+                /* Create an NV_SW object for various sync purposes */
+                ret = nouveau_gpuobj_gr_new(chan, NvSw, NV_SW);
+                if (ret)
+                        return ret;
 
-        /* Create an NV_SW object for various sync purposes */
-        ret = nouveau_gpuobj_gr_new(chan, NvSw, NV_SW);
-        if (ret)
-                return ret;
+                ret = RING_SPACE(chan, 2);
+                if (ret)
+                        return ret;
 
-        /* we leave subchannel empty for nvc0 */
-        ret = RING_SPACE(chan, 2);
-        if (ret)
-                return ret;
-        BEGIN_RING(chan, NvSubSw, 0, 1);
-        OUT_RING(chan, NvSw);
+                BEGIN_RING(chan, NvSubSw, 0, 1);
+                OUT_RING  (chan, NvSw);
+                FIRE_RING (chan);
+        }
 
-        /* Create a DMA object for the shared cross-channel sync area. */
+        /* Setup area of memory shared between all channels for x-chan sync */
         if (USE_SEMA(dev) && dev_priv->chipset < 0x84) {
                 struct ttm_mem_reg *mem = &dev_priv->fence.bo->bo.mem;
 
@@ -534,23 +540,8 @@ nouveau_fence_channel_init(struct nouveau_channel *chan)
                 nouveau_gpuobj_ref(NULL, &obj);
                 if (ret)
                         return ret;
-
-                ret = RING_SPACE(chan, 2);
-                if (ret)
-                        return ret;
-                BEGIN_RING(chan, NvSubSw, NV_SW_DMA_SEMAPHORE, 1);
-                OUT_RING(chan, NvSema);
-        } else {
-                ret = RING_SPACE(chan, 2);
-                if (ret)
-                        return ret;
-                BEGIN_RING(chan, NvSubSw, NV_SW_DMA_SEMAPHORE, 1);
-                OUT_RING  (chan, chan->vram_handle); /* whole VM */
         }
 
-        FIRE_RING(chan);
-
-out_initialised:
         INIT_LIST_HEAD(&chan->fence.pending);
         spin_lock_init(&chan->fence.lock);
         atomic_set(&chan->fence.last_sequence_irq, 0);