Comment 9 for bug 158017

Both /etc/pam.d/gdm and /etc/pam.d/gnome-screensaver contain:
auth optional

However, only the former contains:
session optional auto_start

That's how it should be according to the documentation:

Is gnome-keyring-daemon supposed to be killed on hibernate? If that's the case, then it should be sufficient to append auto_start to the end of the auth line in /etc/pam.d/gnome-screensaver, since that pam module checks if the keyring daemon is already running and doesn't start it again if it is.