Messages in this thread | | | Date | Thu, 09 Dec 1999 15:38:55 -0500 | From | Jeff Garzik <> | Subject | Re: 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?
case SNDCTL_DSP_SETDUPLEX: 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 majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |