To be honest, I'm not entirely sure if pm-utils is causing the problem. It's possible that the issue is in the kernel, but I've checked several different ones without any interesting results.
** Package changed: ubuntu => pm-utils (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2066129 Title: The external monitor does not wake up from sleep at 4K resolution To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pm-utils/+bug/2066129/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs