[pulseaudio-discuss] 'Failed to find a working profile' for firewire sound devices
David Henningsson
david.henningsson at canonical.com
Wed Jan 22 08:49:30 PST 2014
On 01/16/2014 04:37 AM, Takashi Sakamoto wrote:
>> 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.
Hmm, it seems you're right, as this is done in alsa-lib. But I guess
it's mostly a minor optimisation to remove it. Calling snd_pcm_prepare
an extra time should not have any effect, I guess...
>
> I think that snd_pcm_prepare() should be called when recovering from any
> XRUNs or suspend.
>
>
> Regards
>
> Takashi Sakamoto
>
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic
More information about the pulseaudio-discuss
mailing list