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

David Henningsson david.henningsson at canonical.com
Wed Jan 15 12:10:39 PST 2014

On 01/15/2014 03:54 PM, Takashi Sakamoto wrote:
> When I playback with 2ch application, then the samples are going to
> every available channels.

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

> And I mind that PulseAudio tries the same times as the number of
> settings in multichannels.conf. Each trial call snd_pcm_prepare() in the
> end of snd_pcm_hw_params().
> This is a bit problem for the devices because the drivers start stream
> when snd_pcm_prepare() is called.

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.

>> ...but we might want a better match than just "firewire" in order not to
>> catch the firewire speakers (if they have normal alsa mixers instead of
>> hwdep control).
> Firewire speakers are just three models.
> (Vendor ID/Model ID)
> iSight:  0x000a27:0x000010
> Griffin: 0x001292:0x00f970
> Lacie:   0x00d04b:0x00f970
> So we can write udev rules for them to distinguish from the others.
> Please refer to '60-ffado.rules'.

Ok, good.

David Henningsson, Canonical Ltd.

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