Re: Re: [Alsa-user] AD1985 full-duplex(?)

[Takashi Iwai <tiwai@suse.de>]

At Tue, 28 Sep 2004 10:57:26 -0400,
Paul Davis wrote:
> 
> >current ALSA could not meet my requirements because of 
> >swapping/scheduling effects which makes distorted sound in normal non RT 
> >apps. Doing just a few more calls doesn't help in this case ;-[.
> 
> oh c'mon. thats not ALSA. the *kernel* can't meet your
> requirements. ALSA has nothing to do with it. OSS apps and drivers
> can't change the way the kernel schedules tasks. the same broken
> device drivers will coexist with any kernel-side API that you
> propose. you're mistaking where these issues exist.

I agree with Paul.  It's the kernel issue.  For example, with the Con
Kolivas's patch, you can choose another scheduler class which works
much better in such a situation (it's a kind of safe soft-RT w/o root
priv).

However, having a functionality to creata a kernel-thread (with a
slightly higher priority) for the large intermediate buffer handling
sounds not too difficult.  It might be even a good idea - at least,
all opererations can be transparent.

This will offer the more stable playback but of course much worse
audio control.  But it will surely make the life of some people easier
:)


Takashi


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