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 Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1242321 Title: USB 3.0 Harddrive not recognised Status in linux package in Ubuntu: Confirmed Bug description: Ubuntu is not recognising any device plugged into any USB 3.0 ports. Sometimes Ubuntu will freeze for a few seconds when you plug something into a USB 3.0 port; when Ubuntu comes out of the freeze, the device is still NOT recognised. No problems with USB 2.0 ports and devices. The USB 3.0 on this computer only works in Windows 7 (I'm dual booting Ubuntu 13.10 and Windows 7, both are 64-bit). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1242321/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp