/dev/raw and /dev/mem

[sridhar vaidyanathan]

I attempetd to transfer data from a raw char device to a buffer allocated by 
mmaping /dev/mem. But the operation failed with 'Bad Address'.Upon a bit of 
investigation I found that VM_IO flag is set in the mmaped pages.get_user_pages
() which is called by the raw character driver doesn't like this.I am not very 
clear about the reason.
Is it not possible to do this?
-sridhar
ps: email me as i am not subscribed.