[alsa-devel] softvol plug-in dependancies?

Simon Dunn sdunn at mpc-data.co.uk
Sat May 17 12:53:39 CEST 2008

> Which ALSA version, which driver and how is your configuration setup?
> The softvol itself is known to work in most cases, but of course,
> there could be remaining bugs.  But, I suspect it's rather specific to
> your use-case...

Hi Takashi,

Thanks for your reply.

The version of ALSA lib and utils I'm mainly using is 1.0.10, though I've
tried version 1.0.16 and get the same results.

The Linux kernel I'm using is version 2.6.10, which includes the ALSA
driver architecture version 1.0.6.

I'm running this on a freescale mcf5475, Coldfire based platform.

I've reverted to using the dummy driver and a very basic asound.conf file,
see below, but still no joy with the plug-in.

It's the output from running amixer, once the softvol control is enabled,
that I find most curious.  Listing its contents just seems to produce an
uninitialised device.  Given the big endian nature of the cpu I'm
suspicious that this may be an endian bug, though after spending a couple
of days examining the alsa-lib code I've failed to find anything wrong up
to now, obviously ;)

Has the softvol plug-in been used on a big endian system to your knowledge?

Running amixer shows the controls implemented in the Dummy driver perfectly
well, and these can be adjusted using amixer or alsamixer.

The DMIX plug-in works just fine so if it is a bug, endian or otherwise,
then it is probably limited to the softvol plug-in rather than alsa-lib in

Any help or suggestions you can provide is greatly appreciated.



pcm.globalvol {
     type            softvol
     slave.pcm       "hw:0,0"
     control.name    "GLOBAL Vol"
     control.card    0


Simon Dunn, Software Engineer
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