[alsa-devel] [PATCH v2 00/10] ALSA: usb-audio: fix playback/capture concurrent usage

[Eldad Zack]

On Thu, 22 Aug 2013, Eldad Zack wrote:
> On Thu, 22 Aug 2013, Daniel Mack wrote:
> > On 22.08.2013 19:43, Eldad Zack wrote:
> > > On Thu, 22 Aug 2013, Daniel Mack wrote:
> > >> On 21.08.2013 23:37, Eldad Zack wrote:
> > >>> Hi,
> > >>>
> > >>> This patch series attempts to fix a long starting problem with the concurrent
> > >>> usage of playback and capture on implicit feedback devices.
> > >>>
> > >>> Applies against current for-next (HEAD b43dd416be21bc8ad60984e13def032f01aaaa18 ).
> > >>
> > >> Thanks a lot for working on this! I'll give that series a test run tonight.
> > > 
> > > That's great, thanks!
> > 
> > So, with your patches applied, I'm getting the NULL pointer Oops below
> > just by plugging in a UAC2 sound card.
> > 
> > Note that on this system, pulseaudio is running and grabs the new card
> > immediately, then closes it again. That might be different on your machine.
> > 
> > Do you want me to dig deeper or do you have an idea already?
> 
> Oh, I think that data_endpoint just doesn't get initialized yet, 
> because it opens and closes immediately.
> 
> Does this fix it?

OK, I could easily reproduce this, though I don't have pulseaudio 
installed. Luckily I started working on a regression tester, so I 
modified it to just open and close (it's trivial, but if anyone is 
interested, I can post it). 
This fixes it for me.

Sorry about the oops and thank you very much for testing!

I also need to fix an error in the code (the altset_idx/altsetting issue 
Clemens pointed out), so you might want to wait until I post a revised 
patchset.

Cheers,
Eldad