Pinning X.org

[hdv@jadev.org (J.A. de Vries)]

Hi,

I need to upgrade my laptop without upgrading X.org. The laptop is a
reasonably up-to-date etch install with X.org 7.0.22 and proprietary
drivers from ATI. (As soon as I have time and can risk a non-working X
server I'll upgrade those too.)

I want to pin X.org, but am not clear on the dependencies. Is it enough to add  

Package: xorg
Pin: version 7.0.22
Priority: 1001

to /etc/apt/preferences? Or do I need to add all dependencies too?

Thanks for your help.

Grx HdV