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

Takashi Sakamoto o-takashi at sakamocchi.jp
Mon Jan 13 18:22:19 PST 2014

 > They are quite unusual, that's why I reasked.

I think this type of questions can't help to resolve this issue at all...

 > I wanted to know whether these relationships are indeed due to
 > the hardware limitations, or due to your driver being too simplistic

I've already answered this:
 > AFAIK, the driver should support what the hardware supports.
Yes. It's my intent to add the rules between channels/rates.

 > I have looked at the source. There are comments mentioning tables 50
 > and 51. Is that datasheet (for bebob) publicly available?

It's closed. The line is just a pointer for to refer to the documents. 
It's just for a few developers.

 > I guess the best course of action would be to reask on alsa-devel.

I have an thought that this is an issue in PulseAudio-side. So I can 
post to alsa-devel to gather good ideas, not to resolve this issue.

Here, I introduce my thought for this issue:

1.0 'alsa-lib' already gives a way to resolve channels/rates/formats 
mismatch between applications and ALSA drivers.
1.2.It's 'plug' plugin.
1.3.Source package of 'alsa-lib' includes default configurations. It's 
applied to all of PCM drivers. All of PCM drivers have 'plughw' in 
user-land configuration.
1.4.Then ALSA applications can resolve channels/rate/formats mismatch 
with 'plughw'.

2.0 In a relationships to ALSA, PulseAudio is one of ALSA applications.
2.1 PulseAudio opens ALSA PCM handler with flag of 
2.2 This means 'When PulseAudio resolve such mismatch, PulseAudio don't 
use alsa-lib functionality, just manage by itself'.
2.3 This strategy works well for 'typical' sound devices with 
stereo/surrund channels.
2.4 But once PulseAudio encounter 'non-typical' sound devices, it fails 
to detect automatically.

3.0 One of 'non-typical' is ICE1712 based sound device.
3.1 ICE1712 has simple rules for its channels/rates.
3.2 So configuration with 'route' plugin can be a solution for this issue.
3.3 Then, for ICE1712, PulseAudio doesn't follow strategy 2.2. 
PulseAudio uses 'alsa-lib' functionality.
3.4 This was a solution for this issue, at a glance.

4.0 One of 'non-typical' is Firewire sound device for studio use.
4.1 This type of devices have variety of channels/rates.
4.2 So a solution with 'route' plugin can't apply.
4.3 Then this issue appears again.

(When applying a solution with 'route' plugin, I must maintain much 
files for each configuration of devices. It may be over 100 
configurations in 'alsa-lib'. This is... this is...this is not 


Takashi Sakamoto
o-takashi at sakamocchi.jp

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