[Sound-open-firmware] Input/output error for simple pipeline with mixer

[Daniel Baluta]

Hi Tomasz, Karol, Ranjani,

I wonder if you have any clues on why $subject happens.

We have a simple pipeline like this:

PCM0  --> B0--+
                         |--mixer-->B1-->DAI
PCM1 --> B1--+

Subdevices are created like this:

oot at imx8qxpc0mek:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sofwm8960audio [sof-wm8960-audio], device 0: Port0 (*) []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: sofwm8960audio [sof-wm8960-audio], device 1: Passthrough
Playback 1 (*) []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

But, when we use aplay in the following order:

$ (1) aplay -Dhw:0,1 -f S32_LE -c 2 -r 48000 file1.wav
$ (2) aplay -Dhw:0,0 -f S32_LE -c 2 -r 48000 file0.wav

everything is OK, mixing works.

But when the order is reversed:

$ (2) aplay -Dhw:0,0 -f S32_LE -c 2 -r 48000 file0.wav
$ (1) aplay -Dhw:0,1 -f S32_LE -c 2 -r 48000 file1.wav

(1) aplay exists with an error:
aplay: pcm_write:2057: write error: Input/output error

I wonder if you met this. Topology looks to be symmetric
with respect to PCM0/PCM1.