diff --git a/.circleci/test.yml b/.circleci/test.yml
index 19a25a8610..974f432885 100644
--- a/.circleci/test.yml
+++ b/.circleci/test.yml
@@ -65,7 +65,7 @@ jobs:
           command: |
             pip install git+ssh://git@github.com/open-mmlab/mmengine.git@main
             pip install -U openmim
-            mim install 'mmcv >= 2.0.0rc4'
+            mim install 'mmcv>=2.0.0rc4,<2.2.0'
             pip install git+ssh://git@github.com/open-mmlab/mmdetection.git@dev-3.x
             pip install -r requirements/tests.txt
       - run:
@@ -118,7 +118,7 @@ jobs:
           command: |
             docker exec mmdet3d pip install -e /mmengine
             docker exec mmdet3d pip install -U openmim
-            docker exec mmdet3d mim install 'mmcv >= 2.0.0rc4'
+            docker exec mmdet3d mim install 'mmcv>=2.0.0rc4,<2.2.0'
             docker exec mmdet3d pip install -e /mmdetection
             docker exec mmdet3d pip install -r requirements/tests.txt
       - run:
diff --git a/mmdet3d/models/middle_encoders/voxel_set_abstraction.py b/mmdet3d/models/middle_encoders/voxel_set_abstraction.py
index 366ee4de8a..bdd09bc8c2 100644
--- a/mmdet3d/models/middle_encoders/voxel_set_abstraction.py
+++ b/mmdet3d/models/middle_encoders/voxel_set_abstraction.py
@@ -136,7 +136,7 @@ def interpolate_from_bev_features(self, keypoints: torch.Tensor,
 
         Args:
             keypoints (torch.Tensor): Sampled key points with shape
-                (N1 + N2 + ..., NDim).
+                (B, N, NDim).
             bev_features (torch.Tensor): Bev feature map from the first
                 stage with shape (B, C, H, W).
             batch_size (int): Input batch size.
@@ -144,7 +144,7 @@ def interpolate_from_bev_features(self, keypoints: torch.Tensor,
 
         Returns:
             torch.Tensor: Key points features gather from bev feature
-                map with shape (N1 + N2 + ..., C)
+                map with shape (B, N, C)
         """
         x_idxs = (keypoints[..., 0] -
                   self.point_cloud_range[0]) / self.voxel_size[0]