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

[Takashi Sakamoto]

 > Hmm, I expected the stereo playback to only go to the first two
 > channels. Let me try this later.

I re-check it but it reappears.

 > No, if only "10 channels" is supported, then when trying "8 channels"
> and "12 channels" (and so on), it should not come as far as to starting
> and stopping streams - the driver should return earlier with some error,
> because the channel count does not match with the hw params constraint.

Oops. Yes, you're correct. Thank for your indication.

But then, I mind line 381 in /src/modules/alsa/alsa-util.c.
http://cgit.freedesktop.org/pulseaudio/pulseaudio/tree/src/modules/alsa/alsa-util.c#n381

if ((ret = snd_pcm_prepare(pcm_handle)) < 0) {
     pa_log_info("snd_pcm_prepare() failed: %s", pa_alsa_strerror(ret));
     goto finish;
}

When snd_pcm_hw_params() is success, process reaches this line. Then 
snd_pcm_prepare() is already executed by snd_pcm_hw_params(). So we can 
remove this line.

I think that snd_pcm_prepare() should be called when recovering from any 
XRUNs or suspend.


Regards

Takashi Sakamoto