Update: The problem only happens when my laptop runs on battery. No problem when it runs on ac. Nothing to do with cpu governor or tlp. And it's only happens on external hard disk, no problem with flash disk.
elementary OS Freya 3.13.0-45-generic -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1242321 Title: USB 3.0 Harddrive not recognised To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1242321/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
