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I have a usb keyboard which was working perfectly till now (about a year since i have been regularly using ubuntu). It suddenly stopped working. It stopped working when I connected a USB HDD. Now the keyboard works randomly .. working for a while and then stops working for a longer time. Here is the dmesg output :

[  705.817076] usb 5-1: device not accepting address 8, error -71
[  705.928032] usb 5-1: new low speed USB device using uhci_hcd and address 9
[  706.336060] usb 5-1: device not accepting address 9, error -71
[  706.448055] usb 5-1: new low speed USB device using uhci_hcd and address 10
[  706.568044] usb 5-1: device descriptor read/64, error -71
[  706.792049] usb 5-1: device descriptor read/64, error -71
[  707.008060] usb 5-1: new low speed USB device using uhci_hcd and address 11
[  707.128041] usb 5-1: device descriptor read/64, error -71
[  707.352052] usb 5-1: device descriptor read/64, error -71
[  707.456068] hub 5-0:1.0: unable to enumerate USB device on port 1

Based on the suggestions here i tried the following two things:

echo -1 > /sys/module/usbcore/parameters/autosuspend
echo Y > /sys/module/usbcore/parameters/old_scheme_first

However, i am still facing the same problem. Can anyone help me out with this ? I'm using Ubuntu 10.04 Lucid Lynx.

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1 Answer

Does it work if you unplugged the USB harddisk? If so power could be a problem - each USB port is supposed to give out 500mA of power at 5V only - and with unpowered hub, there may not be enough power for a harddisk (particularly for older harddisk which uses more power).

Try connecting the harddisk through a powered hub.

Otherwise it could be the keyboard problem.

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No, unfortunately the keyboard didn't work after i disconnected the hard disk. I also know that the keyboard is fine since it works on my windows 7 installation. Also as i mentioned the problem is that the keyboard works intermittently. Thanks for the help though. –  tapan Jun 7 '10 at 4:05
    
Does it work with a older/new kernel? IIRC I have seen questions similar to your cases, but in MacOS and that some sort of patch has been made. Give it a shot if you have time. Though I would have ditched the keyboard and get a new one for the matter.... time is precious and keyboards are cheap these days –  bubu Jun 7 '10 at 6:13
    
Yeah, i get your point :). I would still want to figure out whats wrong though :). –  tapan Jun 7 '10 at 7:19
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