I've tested this on a virtual kvm-machine with lucid, and confirmed that:
1. pango-graphite + ttf-sil-doulos disables GDM login (doesn't show up, as note in this bug).
2. Upgrading to the 0.9.3-0.1 version that's available in Debian stable fixes the issues in lucid, seemingly completely.
I'm marking this bug as a duplicate of Bug #540035 and noting down the impact it has on lucid, hopefully it should be possible to sync the version from Debian stable to lucid.
I've tested this on a virtual kvm-machine with lucid, and confirmed that:
1. pango-graphite + ttf-sil-doulos disables GDM login (doesn't show up, as note in this bug).
2. Upgrading to the 0.9.3-0.1 version that's available in Debian stable fixes the issues in lucid, seemingly completely.
I'm marking this bug as a duplicate of Bug #540035 and noting down the impact it has on lucid, hopefully it should be possible to sync the version from Debian stable to lucid.