kmix DCOP call return values wrong?

[David Jarvie]

On Saturday 19 Feb 2005 23:43, Christian Esken wrote:
> Am Samstag, 19. Februar 2005 18:24 schrieb David Jarvie:
> > KAlarm uses KMix to set the master volume when sounds are played with its
> > alarms. But when I use it with KMix from kdemultimedia 3.3.2 (built from
> > source), it doesn't work. I find that the masterVolume() DCOP call to
> > kmix always returns 0, and the setMasterVolume() DCOP call never changes
> > the volume regardless of what value is supplied as a parameter.
>
> This means you have no master volume.
>
> > What has happened here? And will it work in KDE 3.4? (I haven't installed
> > kdemultimedia for KDE 3.4 yet to test it out.)
>
> My guess is that you changed drivers: from OSS to ALSA or vice versa. If
> there is no master volume in the driver, it will never work.

I have changed from SuSE to Debian, each running ALSA. But I have noticed in 
the Debian system that there is an error message during bootup saying 
"Setting up ALSA...done (not loaded)". I haven't bothered to fix this since 
sound seems to work fine despite the error. Perhaps this is the reason that 
there is no master volume.

This does raise the issue for KAlarm as to how to ensure that it is able to 
set the volume when playing sound. It tries to set the absolute volume (i.e. 
independently of the current master volume setting (or however the general 
sound level is set if master volume isn't available)), so that the sound 
level is predictable for the alarm even if the user has changed the system's 
volume setting between setting up the alarm and it being triggered. (Some 
people use it to wake themselves up in the morning, for example.). Is there 
any reliable way of setting the absolute volume regardless of whether ALSA, 
OSS, etc is used, and regardless of whether the master volume exists? Ideally 
I'd like to do it via library calls instead of calling kmix which isn't 
guaranteed to be installed.

Cheers,
David.
KAlarm author.