this affects me as well and i can confirm that it is solved (for me) by installing gdm, which i had removed yesterday: if i remember correctly, after my latest dist-upgrade within quantal, apt-get did alert me that the gdm package was not used anymore and could be removed through apt-get autoremove, which i did.
i have been using lightdm as my DM since before upgrading to quantal from precise.
this affects me as well and i can confirm that it is solved (for me) by installing gdm, which i had removed yesterday: if i remember correctly, after my latest dist-upgrade within quantal, apt-get did alert me that the gdm package was not used anymore and could be removed through apt-get autoremove, which i did.
i have been using lightdm as my DM since before upgrading to quantal from precise.