[Fix] sync_random_seed func adapts to different devices (#10490)

mmdet/core/utils/dist_utils.py

@@ -11,6 +11,8 @@
 from torch._utils import (_flatten_dense_tensors, _take_tensors,
                           _unflatten_dense_tensors)
 
+from mmdet.utils import get_device
+
 
 def _allreduce_coalesced(tensors, world_size, bucket_size_mb=-1):
     if bucket_size_mb > 0:
@@ -154,7 +156,7 @@ def all_reduce_dict(py_dict, op='sum', group=None, to_float=True):
     return out_dict
 
 
-def sync_random_seed(seed=None, device='cuda'):
+def sync_random_seed(seed=None, device=None):
     """Make sure different ranks share the same seed.
 
     All workers must call this function, otherwise it will deadlock.
@@ -171,13 +173,15 @@ def sync_random_seed(seed=None, device='cuda'):
     Args:
         seed (int, Optional): The seed. Default to None.
         device (str): The device where the seed will be put on.
-            Default to 'cuda'.
+            Default to None.
 
     Returns:
         int: Seed to be used.
     """
     if seed is None:
         seed = np.random.randint(2**31)
+    if device is None:
+        device = get_device()
     assert isinstance(seed, int)
 
     rank, world_size = get_dist_info()