I am getting the following error in dmseg on Ubuntu 12.10 as well as Ubuntu 10.04 when I attempt to program my Leonardo over USB.
[275401.132287] usb 6-2: new full speed USB device using uhci_hcd and address 2
[275401.256304] usb 6-2: device descriptor read/64, error -71
[275401.480284] usb 6-2: device descriptor read/64, error -71
[275401.696285] usb 6-2: new full speed USB device using uhci_hcd and address 3
[275401.816281] usb 6-2: device descriptor read/64, error -71
[275402.040099] usb 6-2: device descriptor read/64, error -71
[275402.256276] usb 6-2: new full speed USB device using uhci_hcd and address 4
[275402.664288] usb 6-2: device not accepting address 4, error -71
[275402.776285] usb 6-2: new full speed USB device using uhci_hcd and address 5
[275403.192307] usb 6-2: device not accepting address 5, error -71
[275403.192345] hub 6-0:1.0: unable to enumerate USB device on port 2
This same error (or similar enough, some of the addresses and times changed of course) occurred on both a custom built desktop computer with an old VIA motherboard as well as my much newer Asus UL30-A. However, my friend was able to get it to program perfectly fine using his computer (also running Ubuntu).
Clearly the boards work, so this seems like it is either an issue with Linux drivers (although 12.10 is about as modern as it gets in terms of kernels), hardware (perhaps my desktop and laptop are too old and have some hardware compatibility), or software (perhaps the arduino IDE doesn't quite work right for some unknown reason).
I'm at a loss as to how to troubleshoot this one. It readily programs on one computer, but on both of mine it doesn't. Are there any known issues with hardware level incompatibilities between USB ports and the Leonardo? This seems like it might be a fairly major issue since it effects both of my computers, and both are less than five years old for the motherboards at least... it must effect a reasonable number of other people who similarly can't afford to purchase a new computer more than once every five years or so.
Brian