Disable looking for icon files in home directories

[paulmenzel]

We use a self-build lightdm 1.30.0.

For some reason, AccountsService failed to start in time (longer than 32 seconds), causing lightdm to fall back to its code to enumerate the users. That caused it to mount all home directories, served over NFS in our environment, and we have several hundreds of those. The mount seems to be used to find an icon for the user. Therefore, my colleague patched out that code.

1. Is there a way to disable looking up icons in the home directory?
2. We actually do not list the usernames at all, and the users have to enter those themselves. Is there a way to totally disable looking up users to list them. (It would also save some CPU cycles, I guess.)