[pvrusb2] pvrusb2 got stuck - 0 byte file, kernel panic

[Mike Isely]

On Mon, 2 Feb 2009, Bernhard Geier wrote:

> Hello,
> 
> I'm running a pvrusb2 Hauppauge device which sporadicly gets stuck -
> without any kernel messages. A "cat /dev/video0 > test" results in a 0
> byte file. The PVRUSB is a 24019 Rev C389, Debian stable with kernel
> 2.6.27.13 (self compiled, only patched with netfilter layer 7), pvrusb2
> module from kernel tree.
> 
> A few weeks ago I had kernel 2.6.19 with the pvrusb2-mci-20081019
> module, also getting stuck every few days. But there I was able to
> unload and reload the module without a kernel panic which was sufficient
> to bring the pvrusb2 back to life. No unplug and replug was required,
> just reloading the module.
> 
> In 2.6.27.13 unloading the module failed. When I tried to unplug and
> replug the device's usb cable, I got a kernel panic. After rebooting the
> computer the pvrusb2 worked again.
> 
> See below for the initialization at system boot with the 2.6.27.13
> kernel (hope I got the right lines), the messages when I tried to rmmod
> the module and the kernel panic. Is there anything I could try, at least
> to get some more useful debug messages? I'm pretty sure it will again
> get stuck within the next two weeks...
> 

   [...]

There are 2 problems here :-(

First, the problem with the device getting "stuck" is unforunately 
something that a few others have sporadically seen but so far I have not 
been able to reproduce.  If I can't see it I can't fix it :-(

Second, the kernel panic on module removal is a new issue.  I routinely 
insert / remove the pvrusb2 module from a running system just as a 
result of the usual collection of stuff I do here.  If there is going to 
be a problem with that I usually find out about it quickly.  The last 
kernel I've been testing with is 2.6.27.10; I sure hope the problem 
didn't get introduced with 2.6.27.13.  But from what you've described I 
should be able to reproduce this one pretty easily.

Can you cause the kernel panic ANY time you rmmod the module or only 
when the device is stuck?  If that is the case then it would both 
explain why I haven't seen the panic AND it would give me another way to 
pry at the first problem...

Along the above theme, it would help to characterize the conditions in 
effect when you attempt to do the rmmod and whether or not you get a 
panic, e.g. if the device is plugged in, if an app is using it, if the 
DVB side is locked (streaming), if the device is stuck at the time, etc.  
I have tried pretty hard over time to ensure that under NO circumstance 
can the driver ever cause a panic, but for a hotplugged device like 
this, it is a complex goal to get right and knowing the circumstances 
will help me to pin down the cause.

  -Mike


-- 

Mike Isely
isely @ pobox (dot) com
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