Ok so I'm not sure if the fix is the same for everyone, but in my case
the issue wasn't in the Debian install but in the laptop itself, and
more precisely either in the embedded controler or in some low level
firmware (e1000e or AMT I'd say).
A longer explanation for people interested is at
http://www.corsac.net/index.php?rub=blog&post=1534 in case the fix might
work for other people.
Sorry for the bug hijack if it's completely unrelated.