[pvrusb2] New driver snapshot: pvrusb2-mci-20090616

[Mike Isely]

On Sun, 21 Jun 2009, Mark Goldberg wrote:

> On Sun, Jun 21, 2009 at 7:34 AM, Mike Isely wrote:
> >
> > On Sat, 20 Jun 2009, Mark Goldberg wrote:
> > > I tried this version and using it in mythtv to capture the output of a
> > > sat box the sound
> > > drops out if I change channels. If I stop live tv and then go back to it, the
> > > sound works again.
> > >
> > > Otherwise it seems to work.
> >
> > The audio / video routing is not reset when changing channels.
> > However...  Which device type are you using?  29xxx?
> 
> 24012, from dmesg:
> usbcore: registered new interface driver pvrusb2
> pvrusb2: 20090115 (from www.isely.net):Hauppauge WinTV-PVR-USB2 MPEG2
> Encoder/Tuner
> pvrusb2: Debug mask is 31 (0x1f)
> pvrusb2_a: IR disabled
> cx25840' 0-0044: cx25843-24 found @ 0x88 (pvrusb2_a)
> tuner' 0-0043: chip found @ 0x86 (pvrusb2_a)
> tuner' 0-0061: chip found @ 0xc2 (pvrusb2_a)
> wm8775' 0-001b: chip found @ 0x36 (pvrusb2_a)
> 
> It is just capturing from S video, so the channel change script actually
> only sends out the IR commands to the sat box to change channels.
> If it can be reset from the command line, I can include it in the channel
> change script.

OK, then this isn't what I was suspecting.  There is a known problem 
with 29xxx devices right now where the audio can drop out under certain 
circumstances - but in all cases you have to do something to the device 
itself to trigger the problem.

So what you're telling me is that you're not actually changing any state 
within the device itself - because you're just using the s-video input.  
Yet when you change channels on the upstream source, the audio is gone?  

The pvrusb2-driven device cannot "tell" when there is or isn't audio 
coming into its line-input - it's just an analog unmodulated audio 
signal same as what any stereo system component would work with.  
There's no concept of an audio signal being "present" or not so I don't 
understand how the device could choose those instants in time to lose 
the audio.  Are you sure that you're not actually (deliberately or 
accidentally) sending anything to the pvrusb2 driver when you change 
channels on the sat receiver?  Does anything show up in dmesg when you 
change channels?  There's also additional debug flags we can turn on to 
verify that nothing else is being changed in that instant.

My next suggestion would be to use some RCA Y-adapters to tap the audio 
input for your s-video input and then feed that to something else to 
separately verify that the upstream audio is not going away.  However 
you then said that you can issue more commands to reset the device and 
audio returns so that would seem to disprove this as a cause.

  -Mike

-- 

Mike Isely
isely @ isely (dot) net
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