@cpscotti and The Arsonist : I don't remember to have installed something during the period when GTalk video calls vanished.

The only thing revelant I noticed is the Linux support for Gtalk video calls. It was 2 or 3 days after that. I tested a video call between Ubuntu and the N900.

I think about a protocol evolution or a disable feature from Google. The Gtalk N900 module acts as if there were no cam and no mic.

I gonna try to post the question to google's guys