Re: wacom module bug? "unable to handle kernel paging request..."

On måndag 23 juli 2007, Nicolás Carranza wrote:
> Hello,
> Sometimes after unplugin/plugin my usb wacom tablet, it stops working
> and I get this in my /var/log/messages:
> -----
[kernel oops snip]
> -----
>
> What is wrong?

This is a problem in the input subsystem in the linux kernel. There are some 
locks that are not present that causes this in some cases when you disconnect 
the tablet (I get it on and off both when unplugging and suspending the 
laptop). I've had a look at it but not seen an easy way to add them though..

The only fix after one of these is a reboot (you might need to yank the power 
coord, at least I had to as my distro hung during shutdown). The whole 
USB-subsystem goes by the way...

But the good side is that there are workaround for this. I'm not sure the 
user-space proxy device [linuxwacom-devel, Nov-06 'alternative way to support 
tablet hotplugging'] will help you here. It might be a small timing issue, 
and the user-space program might add sufficient delays that it won't make 
this happened.

If that doesn't help, have a look at the wacomproxy (also a SF-project) kernel 
module that I guaratee does not have the kernel-oops problem (one of the two 
reasons it was written).

Cheers
 Magnus

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