I finally resolved my ALSA problem.

I had to go to Sid and a dist-upgrade later I had a working sound card. However sound was very bad, noisy, it finally went away when I replaced libesd0-alsa by libesd0 (I uninstalled KDE for going to Gnome).

Now it works perfectly, but I still have error messages at boot when an auto-detection tool tries to load the i810_audio modules -OSS driver of my chipset- what I don't want him to do, in fact it's not even compiled with the kernel.

Anyone knows how I could get rid of that autodetect tool?