[pulseaudio-discuss] 'Failed to find a working profile' for firewire sound devices

[Alexander E. Patrakov]

2014/1/12 Takashi Sakamoto <o-takashi at sakamocchi.jp>:
> Then I debug PulseAudio/libasound in a point of 'how to open ALSA PCM
> handle'. I have an presumption that 'plug' plugin can upscale channels
> correctly if PulseAudio open 'plug:hw' device as the same way as
> normal-aplay open.
>
> As a result, I got a conviction that 'SND_PCM_NO_AUTO_CHANNELS' flag for
> snd_pcm_open() disables upscaling.

This is documented at
http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m.html#ga64fa40b556374dabe40d4874242fee19

By "forced channel conversion" they mean the "route" ALSA plugin. See
how it is done in /usr/share/alsa/cards/ICE1712.conf , which is
similar to your use case. Specifically, they try to upscale everything
to 10 channels, because this is what this hardware supports directly.

-- 
Alexander E. Patrakov