Primary for personal use I wrote a little patch to the pam_unix module
so that my Ubuntu desktop system would accept my password even if I
accidentally have my caps-lock key pressed.
https://github.com/pibara/pam_unix
Basically I added a function verify_pwd_hash_caps_ignore to
passverify.c and passverify.h and changed all invocations of
verify_pwd_hash to invocations of verify_pwd_hash_caps_ignore.
https://github.com/pibara/pam_unix/blob/master/passverify.c Line 138..167,1031
https://github.com/pibara/pam_unix/blob/master/support.c Line 645
Its likely not a patch that would be ready for general use, but I feel
that the concept of having caps-lock insensitivity in password
authentication is something that greatly enhances the usability at the
price of just a single bit of password security, and thus is something
that might be very much useful as a general setting for PAM
authentication modules.
Hope someone on this list finds this simple patch useful enough to
expand on it and maybe integrate it into the code-base.
Rob