[pvrusb2] New driver snapshot: pvrusb2-mci-20061003

[Mike Isely]

On Thu, 5 Oct 2006, ervins at latnet.lv wrote:

> >
> > I use mythtv rather then any shell script incantation.  I'm not too bad
> > at shell scripting either I might add.  But mythtv is getting to be
> > rather stable and dummy proof to the point even this dummy is having
> > fewer problems with! :-)
> >
> > Besides, it has an online "tv guide" pvr style database so recording is
> > as easy as clicking on the show to record.  Some of the recording
> > options are somewhat trivial for beginners still as well as some setup
> > options.
> >
>  Actually mythtv is quite bad for things I'm trying to do - recording whatever
> is on composite from xx:xx yo yy:yy. It probably is just too smart. It wants to
> change channels and name programs somehow - it has problems understanding that
> listing is in one timezone and and I'm in another and it had problems
> understanding that I have all interesting channels on composite and cracks up
> when tries to determine what channel I might have on now. It might be also that
> I just don't understand intricate ballance between inputs and channels. :) But I
> will have another try with latest mythtv.  But this is all off-topic. :)
> 
> > If this helps, I usually use something like this:
> > insmod /lib/module/path/to/pvrusb2.ko debug=10
> 
> Thanks for the tip!
> 
> Ervins
> 

Ervins:

I can understand your frustration here with this device, but I think I 
should caution you here that you haven't proven that the PVR USB2 device 
is the cause.  And that if the real problem is say a bad USB cable, dirty 
power, or a flakey USB controller, then you're going to have exactly the 
same problem with whatever device you try next.

There are others here who have run this device for hours at a time.  
There's another pvrusb2 user here whose used one of these devices to 
monitor a camera pointing at a birdhouse, for hours on end.  Certainly 
it's possible that there might be a bug in the driver causing the problem 
you are having, but aside from one report almost a year ago which 
ultimately was found to be a bad USB controller, really nobody else here 
is telling me that they are having this kind of problem.  Is anyone else 
having problems where streaming spontaneously quits after a few hours?  
Please tell me.  Or feel free to "remind" me if you've told me before and 
I've forgotten about it.

Some things I would check:

1. Swap the USB cable.  A bad cable can drop bits, and when that happens 
there will be a loss of sync to the device followed certainly with a 
streaming failure.  Yes, this sort of thing can be rare, but it does 
happen.

2. Check your power situation.  Realize that an external USB device such 
as this does not draw power from the PC with its beefy well-filtered 
supply; it draws from its own cheap barely-filtered power supply.  A 
simple wall-wart switcher like that on the PVR USB2 is not going to be 
anywhere near as resilient against dirty power as a big PC power supply 
can be.  There have been previous reports of people seeing problems when, 
for example, their air conditioning compressor turns on in the house.

3. Check your cooling situation.  If the PVR USB2 is stuffed inside an 
unventilated box it may overheat and will probably glitch.  It does get 
warm; this is an unfortunate effect when a piece of silicon is being used 
to do expensive real-time mpeg2 compression.  Generally, if the device is 
in the open air, and the room isn't overly hot then you should be fine.  I 
only bring this up because if there is a heat-related issue, I imagine 
that long durations spent recording video would probably be a good way to 
push it over the edge.

4. Try a different USB controller, or if you can, plug it into a different 
machine and see if the problem follows.  Marginal USB controllers can drop 
bits and cause behavior similar that possible with a bad USB cable.  And 
I've seen a number of bad USB controllers (though admittedly they all date 
from the early days of the USB 2.0 standard).

I'm not trying to defend how well the driver may or may not work.  Heck, I 
do this for fun and while I try hard to make it as stable as possible, 
nobody's perfect and there certainly could be a new problem in it.  I'm 
not really concerned whether or not you use a PVR USB2 device.  My only 
real concern is that you may not be solving the underlying problem here.  
And that means you're about to spend more money on something else which 
will also misbehave.  So check the above possibilities out; hopefully that 
might lead to a solution (and if it is heat then maybe the solution is 
finding a device that runs cooler).  I'd be curious to hear how this works 
out.

  -Mike


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