[pvrusb2] can't get sound working

[Mike Isely]

On Fri, 30 Jun 2006, Kay Rydyger wrote:

>
> Dear Mailinglist,
>
> I'm trying now for two or three weeks to get the pvrusb2 driver
> working. The problem is that I'm getting no sound. The picture is ok,
> I can also tune the channels. I'm using 2.6.17.1 on ubuntu 6.1 beta
> with pvrusb2-mci-20060607. Naturally, I have consulted the
> information on the Mike's web site, but to no avail. The Hauppauge is
> a 24019RevC289 (2040:2400 Hauppauge).
> Particularly, I played with the port setting of the tda9887, but no
> results. However, I noticed that msp3400 is not loaded. I cannot get
> msp3400 loaded.  Also, after manually loading the msp3400.ko (and/or
> reloading the pvr drivers), nothing happens.
> I include the log messages and the lsmod output here (sorry for the
> long log...):

    [...]

Kay:

Here's some info for you...

You have a 24xxx model series device; this means that you don't need 
msp3400.  For 24xxx devices, the cx25840 chip handles both video and 
audio.  For older 29xxx device, cx25840 is replaced by msp3400 and 
saa7115.  So the msp3400 behavior you are seeing is actually correct.

Right now when a given chip driver (e.g. cx25840) attaches to the pvrusb2 
driver, it gets asked to dump its status *at that point in time* into the 
log.  Since during device initialization you're not streaming anything, 
then seeing the audio muted is actually correct.

You can trigger a status dump at any time by doing

     cat /sys/class/pvrusb2/sn-*/debuginfo

The output to the terminal will be a list of which chip drivers are 
talking to the pvrusb2 driver, but as an additional side effect all those 
chip drivers will also be asked to dump their current state to the system 
log.  So you can do that at any time to see what cx25840 is trying to do 
after you've started streaming from it.  So try that and see if it still 
shows up as muted.

If you don't have the cx25840 firmware extracted and installed, then audio 
likely won't work.  This is a step specific to the 24xxx model series 
hardware.  With the older 29xxx model series msp3400 is used instead (and 
there's no firmware needed for it).  Read the web documentation setup 
section about firmware extraction, and keep in mind that you are dealing 
with a 24xxx device.

You can examine the audio settings at any time through sysfs (in parallel 
with the V4L type controls that an app will handle).  For example

     cat /sys/class/pvrusb2/sn-*/ctl_mute/cur_val

will tell you if the audio is actually muted (from the point of view of 
the pvrusb2 driver).

Do you get any sound at all with anything on this computer?  If you try to 
play a random mpeg file with mplayer do you get any sound?  If not, then 
you might have a soundcard and/or alsa issue.  Another thing you can try 
which is very simple: cat /dev/video0 into a file for say 10 seconds. 
That file will be a valid mpeg2 snippet.  You can then copy that file to 
another computer (where you already know the sound works) and then run 
mplayer on it.  See if you get sound in that case.  If you do this, you'll 
want to pre-tune a valid channel before you run cat (otherwise you will 
just capture static or a blank stream).  (And if you know the frequency 
you want to tune, then you can just echo that value in integer Hz straight 
into ctl_frequency/cur_val.)

My understanding is that tda9887 setup is critical when in PAL (which is 
what I thought I saw in your log).  That being the case, then a tda9887 
foul-up can cause a loss of sound.  However the pvrusb2 driver already 
should be automatically configuring tda9887 for you.  So that should not 
be a cause for trouble.

See if any of that helps to shed some light (or in this case sound) on the 
problem...

   -Mike


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