Comment 33 for bug 1242321

Same problem here, on an Acer Aspire V3-571G. The problem happens with both 14.04 and 14.10 (other versions not thoroughly tested).
Putting USB2 devices in the USB3 ports works.
Putting USB3 devices in the USB2 ports works.
Putting USB2 devices in the USB2 ports works.

Putting USB3 devices in the USB3 ports doesn't work. Copying files to USB3 external hard drives connected to a USB3 port will almost always fail after about 10 seconds. Also, I sometimes get a kernel panic when using the USB3 port on my laptop (both with USB2 and USB3 devices), which might be related.