At Mon, 25 Jun 2007 14:47:50 +0200,
Olivier Galibert wrote:
quoted text
> 
> On Mon, Jun 25, 2007 at 02:40:23PM +0200, Jan Engelhardt wrote:
> > 
> > On Jun 25 2007 14:31, Takashi Iwai wrote:
> > >> It was started in time when most cheap sound cards was without hw mixer.
> > >> And .. when today you use ALSA on sound card without hw mixer still all 
> > >> this (past ?) problems are actual.
> > >
> > >Huh?  I have no problems with soft mixing...
> > 
> > Diverging from the discussion, how is soft mixing actually done? If it was done
> > in userspace, it would need shared memory, or a back relay from kernelspace to
> > userspace (and back again for the final output), otherwise I could not imagine
> > how all alsa streams came together at one point.
> 
> SysV shared memory and semaphores, done in the alsa lib.
> 
> Yes, your kernel sound access library does shared mem, semaphores,
> fork+exec and friends.

FYI, fork+exec was removed long time ago.  shmem and semaphores still
remain, though.


Takashi
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