[pvrusb2] testing pvrusb2

[Mike Isely]

On Thu, 9 Nov 2006, Abe Shan wrote:

> Here is some more relevant information. I only have one USB device (the
> WinTV-PVR-USB2) and I have also tried simply
> cat /dev/video0 > /tmp/rec.mpg
> and even that dies after a few seconds.
> 
> If there are other clues to look for, I would appreciate some hints.

I'd start by looking for 3 possibilities:

1. Something else is touching the device and interfering with it.

2. There is a problem with the USB connection.

3. There is a power problem.

All of those cases have happened to people in the past.

If the USB connection is flakey (e.g. bad cable, bad hub (if you are using 
one), marginal USB controller), then you might get behavior like this.  
I'm not entirely convinced though because if the USB connection is really 
flakey then what you get ultimately will get is the driver completely 
giving up on operating the device - you would have to replug the device to 
recover.  But this sort of thing can be tested for by trying a different 
cable, different controller (if you can), etc.

You might have a power problem with the device.  As an external device, 
the PVR USB2 relies on its own power supply not the PC's power.  And that 
tiny wall-wart is far less robust against dirty power than a PC power 
supply.  So power glitches that might not affect the PC very likely will 
affect the PVR USB2.  Put it on a surge protector or even better a UPS if 
you can.  Running the device off of a UPS might not be a desirable 
solution, but at least just trying it will allow you to either rule out 
this cause or confirm it.

Going back to (1), make sure your mythtv backend is really not touching 
the device when you're trying to test it.  Also, if you have other tuner 
devices present and corresponding software operating said devices, make 
sure that software is really operating the correct device (or just hunt 
down and kill it all temporarily to see if that is a cause).  There was 
one incident a while back IIRC where the addition of the PVR USB2 device 
caused his /dev/videoX entries to get renumbered and an application that 
was operating his "other" device accidentally started trying to manipulate 
the PVR USB2 device.

I can't suggest that any of these causes are definitely the problem.  The 
symptoms you are describing I don't think perfectly fit any of these.  But 
it is a starting point.

Other than that, you could try the device in Windows and see if you 
observe the same bad behavior.  Then it's obviously a defect in the 
hardware and you'll have to RMA it.  I once had a problem on one device 
and spent over a month chasing ghosts in the pvrusb2 driver until another 
person suggested the obvious: try it in Windows.  I did, and saw the same 
exact symptom as what I saw using the pvrusb2 driver.  2 weeks later I had 
a repaired unit back from Hauppauge.

  -Mike

-- 
                        |         Mike Isely          |     PGP fingerprint
     Spammers Die!!     |                             | 03 54 43 4D 75 E5 CC 92
                        |   isely @ pobox (dot) com   | 71 16 01 E2 B5 F5 C1 E8
                        |                             |