drm/amdgpu: take runtime pm reference when we attach a buffer

And drop it when we detach.  If the shared buffer is in vram,
we need to make sure we don't put the device into runtime
suspend.
Acked-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c

@@ -40,6 +40,7 @@
 #include <linux/dma-buf.h>
 #include <linux/dma-fence-array.h>
 #include <linux/pci-p2pdma.h>
+#include <linux/pm_runtime.h>
 
 /**
  * amdgpu_gem_prime_mmap - &drm_driver.gem_prime_mmap implementation
@@ -151,9 +152,13 @@ static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,
 	if (attach->dev->driver == adev->dev->driver)
 		return 0;
 
+	r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
+	if (r < 0)
+		goto out;
+
 	r = amdgpu_bo_reserve(bo, false);
 	if (unlikely(r != 0))
-		return r;
+		goto out;
 
 	/*
 	 * We only create shared fences for internal use, but importers
@@ -165,11 +170,15 @@ static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,
 	 */
 	r = __dma_resv_make_exclusive(bo->tbo.base.resv);
 	if (r)
-		return r;
+		goto out;
 
 	bo->prime_shared_count++;
 	amdgpu_bo_unreserve(bo);
 	return 0;
+
+out:
+	pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+	return r;
 }
 
 /**
@@ -189,6 +198,9 @@ static void amdgpu_dma_buf_detach(struct dma_buf *dmabuf,
 
 	if (attach->dev->driver != adev->dev->driver && bo->prime_shared_count)
 		bo->prime_shared_count--;
+
+	pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
+	pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
 }
 
 /**