Xen Framebuffer is currently broken in upstream:
http://marc.info/?l=linux-kernel&m=121869811531858
http://marc.info/?l=linux-kernel&m=121912581909992&w=2

A fix (http://marc.info/?l=linux-kernel&m=121925882522748&w=2) has been
submitted and is currently between akpm and Linus once it is committed I
intend to add it to the Debian kernel. Hopefully it will find it's way
into a subsequent stable update at some point but I don't want to wait
for that right now.

Ian.
--
Ian Campbell

Biggest security gap -- an open mouth.