[pvrusb2] Black screen, device stuck, need to power cycle to clear

[Mike Isely]

On Mon, 27 Sep 2010, Bill Kristan wrote:

> New problem... my wintv-hvr-1950 now works only briefly, then stops. The
> device node is still there, and I can play it (with mplayer or mythtv), but
> it gives a black screen. The first time I saw this, dmesg gave a "device
> stuck" error from pvrusb2. Removing and loading the module didn't fix it,
> nor did rebooting the computer, but power cycling the capture device did. I
> was able to play /dev/video0 with mplayer, but when I tried to record with
> mythtv I got a black recording again. No error message was reported the
> second time.
> 
> I'm using the firmware extracted from the driver CD.
> 

   [...]

> 
> Not sure what to try ... maybe go back to the firmware from isely.net? Seems
> the version shipped with the device would be best, but it would be something
> to try.
> 

Software normally doesn't "break" by itself - if it was working before 
and you didn't change anything then it should keep working.  (Well this 
isn't quite true; MS software seems able to break by itself...)

If it was working before and now it isn't you have to ask yourself what 
has changed?  Also, generally if it works at all - even briefly - then 
the software is probably OK and you have some other sort of problem.

Based on your description it sounds like the FX2 in the device itself is 
crashing.  Of course that should *never* happen and there's really no 
way for the pvrusb2 driver to cause that, short of downloading corrupted 
FX2 firmware - but even then if it's working briefly then the firmware 
is probably just fine.

I'd probably turn my attention to other possible causes for the device 
to crash.

Is it getting too hot?  (Having it work for a short time before crashing 
each time is something that can be caused by heat.)  I've never heard of 
an HVR-1950 actually overheating, but the other PVR-USB2 models 
sometimes had this sort of issue.  I learned of one case years ago where 
a user had stacked 4 PVR-USB2 devices inside a closed box with no 
ventilation, and that eventually caused the hardware to die from 
overheating.

Is it possible that it's getting hit by power spikes?  Remember that 
your device is getting power from its own little power brick and that 
brick isn't anywhere near as resilient against power line flakiness as 
your PC's internal power supply will be.  I have heard of numerous cases 
where power glitches in the nearby environment (e.g. A/C compressor 
turning on in the house) will crash your capture device.  You could try 
moving it to a different circuit, putting it behind a surge protector, 
or (best choice) plugging it into a UPS.  If any of that helps then the 
problem is dirty power.

Another possibility is that the power brick itself is failing, drifting 
out of tolerance.  This was exactly the problem a while back with the 
Silicon Dust HD HomeRun tuners - they had a bad batch of power bricks 
which would fail after a few months.  Now, I have *NOT* heard of that 
happening here with Hauppauge, but power bricks frequently are a weak 
spot with externally powered devices.

One big lesson I learned years ago when I was messing with TTL circuits 
(yes it was a LONG time ago) - if the circuit is misbehaving then always 
suspect the power first.

Can you run the tuner successfully under *cough* Windows *cough*?  If 
there really is some kind of external problem that's killing the tuner, 
then the answer to that question should be "no".

  -Mike

-- 

Mike Isely
isely @ isely (dot) net
PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8