[Wlug] Missing /dev files

[Karl Hiramoto]

Chuck Noyes wrote:
> On Sun, 30 Mar 2008 21:25:28 -0400
> Mike Frysinger <vapier at gentoo.org> wrote:
>
>   
>> On Sunday 30 March 2008, Chuck Noyes wrote:
>>     
>>> I had mounted an external usb drive /dev/sdb2 onto /media/sdb2 and
>>> was coping several mega-bytes of files to it when I got some I/O
>>> errors. Then I noticed that all of my /dev/sdb* files were missing
>>> from /dev.
>>>
>>> When I do an ls -al /dev, all the files are there except the sdb
>>> files.
>>>
>>> How can I get these back? I'm running Ubuntu 'gutsy'
>>> 2.6.20-16-generic.
>>>       
>> the device nodes only exist as the kernel thinks the device exists.
>> if you got I/O errors and then the device nodes disappeared, the
>> kernel probably detached the device.  so even if you made the device
>> nodes by hand, it wouldnt matter as the kernel still wouldnt think
>> the device was attached. review your `dmesg` and if need be,
>> unplug/plug in the USB device. -mike
>>     
>
> dmesg shows many entries like this:
>
> new high speed USB device using ehci_hcd and address 10
> usb 5-3: device descriptor read/8, error -110
> usb 5-3: device descriptor read/8, error -110
>
> Googling this message doesn't seem to provide much help.
>
> I have unpluged the device and even rebooted the computer. However,
> after a reboot, the /dev/sdb* files are still missing.
>
>   
The device files should be created by udev automatically when you 
pluging the device, or boot the PC..   When you un/plug the device you 
should see some info in dmesg.    Perhaps you have some kind of error 
occurring.   you could try rmmod "ehci_hcd" to try using USB 1.1 instead 
of usb 2.0.   You could also try plugging it into a different hub or usb 
port on the PC.

-- 

--
Karl Hiramoto  http://karl.hiramoto.org/