I think I have found the cause: openntpd. The keyboard begins stuttering in the exact moment that ntpd is stepping time because of a great offset. Keyboard works if I disable ntpd and stops working if I start it then. I have tested this on the second computer and will test it now on the first one. I cannot confirm this now, but it seems like time runs much too fast in dom0 (this is on the computer where the CPU clock speed is reported correctly), and this leads to ntpd stepping the time back for as much as 4 seconds at once.
-- [edgy] keyboard broken in X11 on xen dom0 https://launchpad.net/bugs/67519 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
