I am seeing this same issue on two separate Z87 boards from Asus on Gentoo. It looks like the culprit is the Asmedia USB 3 controller, at least from my end.
Cutting power to the system and powering on allows the init sequence to complete normally. Upon reboot or regular power on, the device with ID 174c:2074 ASMedia Technology Inc. fails to load throwing the unable to enumerate USB device message in dmesg. I started noticing this problem when I switched to a 4.0 kernel on Gentoo. Subscribing to follow up on this issue. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1437492 Title: boot stalls on USB detection errors To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1437492/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
