Re: volume PCM plugin

[Takashi Iwai <tiwai@suse.de>]

At Mon, 17 Jan 2005 15:17:36 +0600,
Petr Gladkikh wrote:
> 
> Hello.
> 
> Here is the patch (for alsa-lib-1.0.7) which is another attempt 
> (compare to coftvol plugin) to emulate volume control in alsa-lib (see 
> my previous post). The volume plugin is based on copy PCM plugin.

Thanks for the patch.

> IMO the approach which is used here would allow more flexible 
> configurations than softvol. E.g. it allows bind to master volume 
> control in addition to emulated volume control. If necessary the 
> volume plugin allows to easily extend number of hooks which can be 
> attached to it (for now only one is supported).

Handling with pthread looks nice.  The only concern is that I'm not
100% sure whether pthread works in every application.

As in my last reply, the other features can be easiply implemented in
softvol (the patch was attached there).  The multiple hooks are easy
to add as well.

So, for my eyes, only missing feature is the optimization of volume
control change via pthread and poll().  Although ioctl is relative
fast, it's of course better to eliminate to call at each time.
Maybe we can the behavior selectable via config option.
(The best optimization for this would be (read-only) mmap of
 contorls, but it's not implemented :)

IMO, adding multiple plugins which work almost identically is just
confusing.  Let's integrate them, instead.


Takashi


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