I believe I'm experiencing this issue as well. If lightdm loads up, I enter half my password and the flickering happens, I type the rest of my password and am not able to login. I believe the flickering interrupts my typing somehow. When I retype my password entirely after the flickering, it works fine.
Ubuntu MATE 16.04 Ubuntu MATE desktop 1.12.1 CPU: Intel Core i7-6500U CPU @ 3.1GHz GPU: Mesa DRI Intel(R) HD Graphics 520 (Skylake GT2) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1531224 Title: lightdm-gtk-greeter flickers once little after lightdm starts To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/1531224/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
