[alsa-devel] Zoom R16/24 playback slient

[Ricard Wanderlof]

On Tue, 6 Oct 2015, Panu Matilainen wrote:

> > At the moment I'm considering adding some additional code to
> > sound/usb/pcm.c: prepare_playback_urb(), governed by a new boolean in
> > struct snd_usb_substream in a similar vain as txfr_quirk in that structure
> > (which in turn is set in some quirk function detecting the R16).
> >
> > What needs to be done is to add 4 bytes to the length, and adjust the
> > offset accordingly, in urb->iso_frame_desc[i], and then add the additional
> > length descriptor for each packet when copying out the data further down
> > in the same function.
> >
> > It would be nice to add a foo_quirk() function but since the actual
> > copying of the data needs to be changed, it's not really possible to do
> > efficiently with a separate routine.
> 
> Sounds like a plan to me, but keep in mind I'm just another newbie in 
> all this. Anyway, I wouldn't worry about cleanest possible way at this 
> point, just do a quick-n-dirty hack to see if adding the length is 
> enough to get it working and worry about the rest later. I'll try to 
> have a look at it too as soon as time permits, but meanwhile if more 
> experienced people have better suggestions...

Yes, a proof-of-concept is needed, and there may be further issues, but 
I'm hoping for some input too from the 'more experienced people' if this 
is the right way to go about it before I go to far in the wrong direction.

/Ricard
-- 
Ricard Wolf Wanderlöf                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
Phone +46 46 272 2016                           Fax +46 46 13 61 30