Re: [Jack-Devel] ALSA PCM multi plugin and xruns

On Sat, Dec 8, 2012 at 3:38 AM, Devin Anderson
<[hidden]> wrote:

> IIUC, the 'xruns' are generated because there *is* data available to
> be read, but there *isn't* enough data, which means 0 is returned,
> which incorrectly indicates that an xrun happened.  The exception is
> when both `capture_avail` and `playback_avail` are both set to 0.
> Perhaps userspace hasn't been told about new samples in the kernel
> ringbuffer.

I read through the ALSA multi plugin source a bit.  I now see that
poll descriptors are only returned for one device (the *master*
device), while the amount of available samples is calculated by
looking at all the slave devices and returning the minimum amount of
samples available.  This leads me to believe that the poll descriptors
indicate that there is data available on the master device, but there
isn't any data available on one of the other slave devices.

I'll try to figure this out tomorrow.  I need sleep.

-- 
Devin Anderson
surfacepatterns (at) gmail (dot) com

blog - http://surfacepatterns.blogspot.com/
psinsights - http://psinsights.googlecode.com/
synthclone - http://synthclone.googlecode.com/

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