[linux-dvb] Another Nova-T 500 Dual DVB-T Oops

[Matt Doran]

Patrick Boettcher wrote:
> On Tue, 6 Feb 2007, Chris Johns wrote:
>
>   
>> Patrick Boettcher wrote:
>>     
>>> I'm not exactly sure what needs to and what can be done.
>>>
>>>       
>> I would like to stop the kernel oops. Having the kernel crash is a pain.
>>     
>
> My question was related to USB debugging - I'm not sure what can be done 
> on the USB side to see some more information (why is there a disconnect).
>
> Maybe something can be done with the ehci-module.
>
>   
>> Feb  6 17:23:20 localhost kernel: urb completition error -32.
>> Feb  6 17:23:20 localhost kernel: urb completition error -71.
>> Feb  6 17:23:20 localhost last message repeated 347 times
>> Feb  6 17:23:20 localhost kernel: usb 8-1: USB disconnect, address 2
>> Feb  6 17:23:20 localhost kernel: ehci_hcd 0000:02:02.2: qh f6902180 (#82)
>>     


I asked a few questions on the linux-usb-dev list.  They said the best 
way to track down this problem is to run usbmon and log the USB traffic 
on the device until the problem occurs.  The quote:

> I suppose you can run usbmon constantly and have it dumping the traffic
> in a file, if your disk is big enough. Then if the device disconnects,
> we'll see the preceeding traffic and may be able to make deductions.
> Please look if your system has this file:
> /usr/share/doc/kernel-*/Documentation/usb/usbmon.txt
>
> This is not guaranteed to work, because sometimes devices just disconnect
> for no good reason, e.g. if they have bad power or a cables are not 
> shielded
> well. But I don't have better ideas.

Another of the developers said they they just tracked down a kernel bug 
in USB core that didn't make it into 2.6.20.  The details and the patch 
are here:

    http://sourceforge.net/mailarchive/message.php?msg_id=38138485

I plan to compile this up and see if it improves things.  But haven't 
had a chance yet.

Cheers,
Matt
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