[lkml]   [1999]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Number of sound channels?
Thomas Sailer wrote:
> Alan Cox wrote:
> >
> > > The Via audio chip has a single read channel and a single write
> > > channel. Do I treat this as a single channel with read and write
> > > capability, or two separate channels?
> >
> > Single full duplex I think
> Mostly I do it both ways - if /dev/dsp is opened O_RDONLY (or O_WRONLY),
> another process is allowed to open it O_WRONLY (or O_RDONLY). If it
> opens O_RDWR, noone else is allowed.

This is how I implemented via_dsp_open as well.

Is this why USB's audio device handling of SNDCTL_DSP_SETDUPLEX is null?

return 0;

> This is sometimes useful, Sun does it also that way (but it only
> works if you can set the sampling rate independently for both
> directions).

Or you have cheap hardware with a fixed sample rate which is the same
for both channels. :) AC97 1.0-compliancy requires at least that.

Jeff Garzik | Just once, I wish we would encounter
Building 1024 | an alien menace that wasn't immune to
MandrakeSoft, Inc. | bullets. -- The Brigadier, "Dr. Who"

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:55    [W:0.035 / U:3.752 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site