Hi, It looks like I'm also experiencing same issue with Lenovo t440p machine and Lenovo Ultra Dock.
This seems to be upsteam bug, one of: https://bugs.freedesktop.org/show_bug.cgi?id=82153 https://bugs.freedesktop.org/show_bug.cgi?id=84718 https://bugs.freedesktop.org/show_bug.cgi?id=80355 -- WBR, Dmitry -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
