[pulseaudio-discuss] Alsa output devices, able to use alsa plugin?

[Ng Oon-Ee]

On Wed, 2009-08-26 at 12:27 +0300, Tanu Kaskinen wrote:
> ke, 2009-08-26 kello 16:48 +0800, Ng Oon-Ee kirjoitti:
> > 
> > pcm.test {
> >   type plug
> >   slave { pcm "hw:0,0" }
> > }
> > 
> > Which should work, since it doesn't even do anything. I get the same
> > error message trying to load it up though. Could somebody test this out
> > (just have the above in your .asoundrc and try to use 'test' as the
> > device for module-alsa-sink.
> 
> Indeed, it doesn't work. This is the log output:
> 
> D: alsa-util.c: Trying test with SND_PCM_NO_AUTO_FORMAT ...
> D: alsa-util.c: Managed to open test
> D: alsa-util.c: Maximum hw buffer size is 371 ms
> I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa tai hakemistoa ei ole
> I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: Tiedostoa tai hakemistoa ei ole
> D: alsa-util.c: Trying test without SND_PCM_NO_AUTO_FORMAT ...
> D: alsa-util.c: Managed to open test
> D: alsa-util.c: Maximum hw buffer size is 371 ms
> I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa tai hakemistoa ei ole
> I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: Tiedostoa tai hakemistoa ei ole
> D: alsa-util.c: Trying plug:test with SND_PCM_NO_AUTO_FORMAT ...
> D: alsa-util.c: Managed to open plug:test
> D: alsa-util.c: Maximum hw buffer size is 371 ms
> I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa tai hakemistoa ei ole
> I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: Tiedostoa tai hakemistoa ei ole
> D: alsa-util.c: Trying plug:test without SND_PCM_NO_AUTO_FORMAT ...
> D: alsa-util.c: Managed to open plug:test
> D: alsa-util.c: Maximum hw buffer size is 371 ms
> I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa tai hakemistoa ei ole
> I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: Tiedostoa tai hakemistoa ei ole
> I: alsa-util.c: Failed to set hardware parameters on plug:test: Tiedostoa tai hakemistoa ei ole
> E: module.c: Failed to load  module "module-alsa-sink" (argument: "device=test"): initialization failed.
> 
> That "Tiedostoa tai hakemistoa ei ole" error means "No such file or
> directory". I tried also with device=hw:0,0 and device=plughw:0,0 and
> the first worked while the latter gave the same errors. Since the failed
> function calls pertain to buffering, I also tried with tsched=0. It
> worked. So, maybe this is a bug in the "plug" alsa plugin, ie. it
> doesn't implement the *_near() functions properly.
> 
> Lennart, any insights?
> 

Just to add a bit to this (nice thread here for Lennart to read when he
wakes up, i think), I've seen oblique references to this being an issue
with latest Alsa. Specifically there's this giant Pulseaudio with
system-wide equalizer thread on ubuntuforums.org where the latests posts
seem to indicate that the users of the latest versions of Ubuntu
(Karmic, the current alpha/beta due October) aren't able to use the
system-wide equalizer, which relies on the alsa ladspa plugin.

So it does seem as if there's something in latest alsa (.20?) which is
causing this. If I have time over the weekend I may downgrade to .19 and
see if that fixes it.