I installed linux 4.4.0-23.41 from yakkety-proposed, and that fixed the issue.
Fortunately I didn't meet the problem on xenial; the problem was linux 4.4.0-22 on Ubuntu 16.10, but since it's fixed in -proposed, it will soon be history, right? (don't know how to use apport-collect in a situation like this) ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed ** No longer affects: linux (Ubuntu Xenial) ** No longer affects: unity (Ubuntu Xenial) ** Tags removed: xenial -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1584106 Title: Login to Unity session fails with linux 4.4.0-22 Status in linux package in Ubuntu: Confirmed Status in unity package in Ubuntu: New Bug description: My attempts to launch Unity sessions on an updated yakkety fails with linux 4.4.0-22 (both 4.4.0-22.39 and 4.4.0-22.40). Just some blinking on the screen, and I'm thrown back to the greeter. It happens when I try to launch a guest session too, so it shouldn't be anything in my $HOME. linux 4.4.0-21.37 does not trigger this issue. Attaching .xsession-errors. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1584106/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp