Re: emu10k1 device naming

[Lee Revell <rlrevell@joe-job.com>]

On Sun, 2004-07-25 at 04:15, Jaroslav Kysela wrote:
> On Sun, 25 Jul 2004, Lee Revell wrote:
> 
> > Now that the emu10k1 driver supports low latency, multichannel capture,
> > it would be useful to rearrange the devices.  Currently you have to use
> > hw:0,0 for playback, and hw:0,2 for capture.  This works down to 32
> > frames (you have to record more than 2 channels to get 32 frames,
> > because 512 bytes is the smallest period JACK supports).  JACK requires
> > the playback and capture device to be the same for both directions.
> > 
> > The current hw:0,0 device could be moved to hw:0,2.  This is the best
> > arrangement, because these are the only two devices that it makes sense
> > to use for full-duplex.  The hw:0,2 playback device is a special AC3
> > passthrough device, there is no capture device that corresponds to it. 
> > The same applies to the current hw:0,0 (ADC capture) and hw:0,1 (mic
> > capture - 8000 Hz) devices, there is no corresponding playback device.
> > 
> > It was suggsted to use the 'asym' PCM plugin for this, but JACK does not
> > support using a PCM as the device name, you need to give it a hardware
> > device.
> 
> JACK should be corrected. Complain there. I wonder why people always fix 
> the drivers instead of applications.
> 

Good point, this would be much easier to correct in JACK, than fix every
driver to conform.  There actually is no 1:1 correspondence between any
of the capture and playback devices, so it's arbitrary to require the
playback and a capture device to have the same hw index.

Lee



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