Hi Roger, finally solved similar problem with my server. The solution is to add kernel option "PCI=routeirq" while booting (for test if works) and if it does to GRUB_CMDLINE_LINUX in /etc/default/grub. Then run "update-grub".
My GRUB_CMDLINE_LINUX parameter is as follows: GRUB_CMDLINE_LINUX="8250.nr_uarts=5 PCI=routeirq" The former kernel option limits ttySx devices to required number. Hope this will help you. Cheers -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1087519 Title: Serial port ttyS4 doesn't work in 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1087519/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs