This problem appears to be solved by setting GRUB_CMDLINE_LINUX="i8042.nomux=1 i8042.reset" in /etc/default/grub (as advised in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1210748). Looks like it's either buggy hardware or a buggy driver, then.
This problem appears to be solved by setting GRUB_CMDLINE_ LINUX=" i8042.nomux= 1 i8042.reset" in /etc/default/grub (as advised in https:/ /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/1210748). Looks like it's either buggy hardware or a buggy driver, then.