Let's put m>n two nonnegative integers and $Gr:=Grass(n,k^m)$ the grassmanian of the subspaces of dimension $n$ in $k^m$. We have a natural immersion $Gr \subset P({\Lambda}^{n} k^m)$ and I call $C(Gr) \subset {\Lambda}^{n} k^m$ the affine cone above $Gr$. 
If we blow-up $C(Gr)$, we always obtain something smotth, but my question is: 
Is the blow-up a crepant resolution of the singularities of $C(Gr)$?   
In fact the answer is no when n=1 or n=m-1, but what happens in the other cases ?