[alsa-devel] [PATCH v3 00/11] ALSA: usb-audio: fix playback/capture concurrent usage

[Eldad Zack]

On Sun, 25 Aug 2013, Eldad Zack wrote:

> Hi,
> 
> This patch series attempts to fix a long standing problem with the concurrent
> usage of playback and capture on implicit feedback devices.

My crude regression tester caught a problem causing the streams to 
fail with this order (though it doesn't trip any WARNs or oops):

++ Test stream permutation 0000013f
  * [1/14] capture => pcm_open
  * [2/14] capture => pcm_hw_params
  * [3/14] capture => pcm_prepare
  * [4/14] capture => pcm_start
  * [5/14] capture => waitsleep
  * [6/14] capture => pcm_stop
  ++ Frames [capture]: 39360
  * [7/14] playback => pcm_open
  * [8/14] playback => pcm_hw_params
  * [9/14] capture => pcm_close
  * [10/14] playback => pcm_prepare
  * [11/14] playback => pcm_start
  * [12/14] playback => waitsleep
  * [13/14] playback => pcm_stop
  ++ Frames [playback]: 101760
  * [14/14] playback => pcm_close
++ Test stream permutation 0000015f
  * [1/14] capture => pcm_open
  * [2/14] capture => pcm_hw_params
  * [3/14] capture => pcm_prepare
  * [4/14] capture => pcm_start
  * [5/14] capture => waitsleep
  * [6/14] playback => pcm_open
  * [7/14] capture => pcm_stop
  ++ Frames [capture]: 0
!! Test stream permutation 0000015f failed !!

For reference, I ran the tool with my hda-intel card (all 3432 
combinations) and there were no errors.
So it's still doesn't cover all cases.

Cheers,
Eldad