Re: [Jack-Devel] new IIO driver added to jack - large overruns

Just confirming that I also see a similar xrun when running the alsa 
driver ... see below ...
It is possible that this problem is within Jack itself, and not the 
drivers ...

Matt

  jackd -r -d alsa
jackd 0.124.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn 
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details

JACK compiled with System V SHM support.
loading driver ..
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
ALSA: Cannot open PCM device alsa_pcm for capture. Falling back to 
playback-only mode
configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
ALSA: final selected sample format for playback: 16bit little-endian
ALSA: use 2 periods for playback

**** alsa_pcm: xrun of at least 71.259 msecs

**** alsa_pcm: xrun of at least 71.001 msecs

**** alsa_pcm: xrun of at least 71.038 msecs

**** alsa_pcm: xrun of at least 71.019 msecs


On 20/01/14 20:35, Matt Flax wrote:
> Hi there,
>
> I have added a new IIO driver to jack.
> IIO is Industrial IO and it is for devices with high sample rates.
> Currently it is only partially tested with devices which have the 
> AD7476A chips onboard - they have a 1MHz sample rate which is rather 
> nice :) However I have a problem ... please read on ...
>
> As I don't have write access to the original jack1 repo, I have forked 
> until I do. For now you can find it here :
> https://github.com/flatmax/jack1
>
> You will also need the git repo for gtkiostream, as it uses this code :
> http://www.flatmax.org/gtkiostream/html/classIIO.html
>
> This new IIO driver is in alpha mode... I am currently testing on an 
> ARM board however I get large overruns for some reason ...
>
> Here is an example when running 'jackd -r -d iio' :
>
> created iio driver ... iio_pcm|1000000|1024|1024|4|0
> iio_driver_start::   enabling IIO : enable(true)
> iio_driver_wait
> iio_driver_wait
> **** iio: xrun of 97145 usec
> iio_driver_wait
> **** iio: xrun of 81626 usec
> iio_driver_wait
> **** iio: xrun of 80022 usec
> iio_driver_wait
> **** iio: xrun of 79894 usec
> iio_driver_wait
> **** iio: xrun of 79856 usec
> iio_driver_wait
>
>
> I am actually wondering whether anyone can help me with some information ?
> I run the driver with zero load ... it doesn't ever try to read 
> anything from the actual devices ... however it appears that jack on 
> the ARM board is giving Xruns of the order of 80 ms !
>
> This is even when the driver_read function is as follows :
> static int iio_driver_read (iio_driver_t *driver, jack_nframes_t 
> nframes) {
>   return 0;
> }
>
> The relevant driver code is located here :
> https://github.com/flatmax/jack1/blob/master/drivers/iio/iio_driver.C
>
> It uses the g++ compiler because it instantiates the IIO class from 
> gtkiostream to do the heavy lifting.
>
> Matt
>
>
> 
> Jack-Devel mailing list
> [hidden]
> http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org

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