Julien,I reproduced this bug on current wheezy without the troublesome boot parameters.
Linux minerva 3.2.0-3-amd64 #1 SMP Thu Jun 28 09:07:26 UTC 2012 x86_64 GNU/Linux
jgoerzen@minerva:~$ cat /proc/cmdlineBOOT_IMAGE=/boot/vmlinuz-3.2.0-3-amd64 root=/dev/mapper/minerva-root ro quiet pcie_aspm=force i915.lvds_downclock=1
Does this meet your requirements? thanks, -- John