I'm having this poblem sfor a long time (maybe since the beginning almost).
Gdm will not let me login with my password, while kdm will ...
Gdm/pam complains it cannot recognize the option "service=..." with
auth required /lib/security/pam_unix.so service=system-auth
The other stages can use pam_unix.so with the option it seems. I don't really have an idea how to solve this ... I tried to change the auth-line(to the one of kdm I think), but then suddenly gdm would let me login without a password ... kdm asks a a password and seems to verify it ...
I would like to use gdm since I use gnome and it needs it if you want to open a new session ... (btw kdm and gdm should start using the same interface or so ... it's really annoying you can't start a new session in gnoem if you use kdm and the same for gdm and kde I suppose ...)