On Sat, 12 Oct 2002, Abramo Bagnara wrote:
> Jaroslav Kysela wrote:
> >
> >
> > In this case, I propose to change snd_pcm_avail() to snd_pcm_hwsync()
> > function with description: "synchronize r/w pointers with hardware".
> > Really, after some thinking, the return value from snd_pcm_avail() cannot
> > be used for nothing serious. I simply don't like that delay() functions
> > do more arithmetic than necessary. Overdesign has been criticized in this
> > list, too.
>
> Let examine kernel level: snd_pcm_{plaback,capture}_delay do a
> snd_pcm_update_hw_ptr and a snd_pcm_{playback_hw,capture}_avail (that's
> only a wrap safe difference).
>
> Are you sure you want to add another ioctl and another API function in
> all the PCM classes just to avoid a subtraction?
You've already noted that delay() expression might be more complex, so the
code path eats more CPU than needed for sync operation.
Jaroslav
-----
Jaroslav Kysela <[EMAIL PROTECTED]>
Linux Kernel Sound Maintainer
ALSA Project http://www.alsa-project.org
SuSE Linux http://www.suse.com
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