[ALSA - driver 0000818]: Web browsing in Mozilla causes ADAT clocks on HDSP 9652 to be invalid

[bugtrack@alsa-project.org]

The following issue has been REOPENED.
======================================================================
<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=818> 
======================================================================
Reported By:                Mark Knecht
Assigned To:                charbonnel
======================================================================
Project:                    ALSA - driver
Issue ID:                   818
Category:                   PCI - RME HDSP
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
Distribution:               FC2
Kernel Version:             2.6.8.1-1.520.2vS7.ll.rhfc2.ccrma
======================================================================
Date Submitted:             01-14-2005 18:35 CET
Last Modified:              02-01-2005 22:12 CET
======================================================================
Summary:                    Web browsing in Mozilla causes ADAT clocks on HDSP
9652 to be invalid
Description: 
In my setup I's using 3 computers:

1) PanetCCRMA with HDSP 9652 as the center of an audio hub

2) Win XP GigaStudio with Hammerfall Light - two ADAT outputs streaming to
HDSP 9652 (ADAT input for clock)

3) Win XP Pro Tools Digi 002 Rack receiving GigaStudio audio from PC
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=2

So the signal flow looks like:

XP         Linux           XP
GSt ====> HDSP 9652 ====> Pro Tools
   <=== (ADAT Clock)

The HDSP 9652 is the master clock for the network. Both XP machine sync to
the HDSP 9652.

When no specific audio apps are running on the Linux box then this
configuration will work for hours if not days with no problems. All audio
data from GSt flows through the HDSP 9652's hardware and the hardware
mixer sends it on to the Pro Tools box. It works perfectly.

When Mozilla is started and I switch from page to page, after a few
minutes I will receive a message on the Pro Tools box that the clock
supplied by the HDSP 9652 was invalid. I can browse the same web pages on
either XP box and I do not corrupt the clocks.
======================================================================

----------------------------------------------------------------------
 charbonnel - 02-01-05 22:07 
----------------------------------------------------------------------
When using the hdsp as a clock source on which your whole studio setup is
dependant (without necessarily running an audio application, e.g. when
doing hardware routing and setting the desired sample rate in hdspconf or
through amixer), here are the options to prevent the audio clock to change
:

* make sure no application uses the card with unpredictable sample rate
requirements (don't use it as the default device, don't use it through the
oss emulation layer)

* make sure that if ever applications access the card, they do it at the
required sample rate (this can be done with the plughw device in your
~/.asoundrc file)

* run an audio application at the desired sample rate. when the device is
opened the clock can't be changed by any other app. typical candidates
here allowing you to keep using the card would be sound daemons (esd,
artsd, jack...)

----------------------------------------------------------------------
 Mark Knecht - 02-01-05 22:12 
----------------------------------------------------------------------
* make sure no application uses the card with unpredictable sample rate
requirements (don't use it as the default device, don't use it through the
oss emulation layer)

[MWK] Not practical but I understand.

* make sure that if ever applications access the card, they do it at the
required sample rate (this can be done with the plughw device in your
~/.asoundrc file)

[MWK] I like this solution but couldn't figure it out myself. If someone
could put a default version on the Alsa HDSP card page that would be a big
help. I'm happy to test.

* run an audio application at the desired sample rate. when the device is
opened the clock can't be changed by any other app. typical candidates
here allowing you to keep using the card would be sound daemons (esd,
artsd, jack...)

Running Jack is a pretty good solution for me. In fact I've been running
it a lot and not seen this problem so possibly I can report (a bit
loosely) that this solution works. Certianly I can do that any time I'm
doing important work.

Thanks!

Issue History
Date Modified  Username       Field                    Change              
======================================================================
01-14-05 18:35 Mark Knecht    New Issue                                    
01-14-05 18:35 Mark Knecht    Distribution              => FC2             
01-14-05 18:35 Mark Knecht    Kernel Version            =>
2.6.8.1-1.520.2vS7.ll.rhfc2.ccrma
02-01-05 21:35 charbonnel     Note Added: 0003466                          
02-01-05 21:46 Mark Knecht    Note Added: 0003470                          
02-01-05 22:03 rlrevell       Note Added: 0003471                          
02-01-05 22:07 charbonnel     Status                   assigned => resolved
02-01-05 22:07 charbonnel     Resolution               open => not an issue
02-01-05 22:07 charbonnel     Note Added: 0003472                          
02-01-05 22:12 Mark Knecht    Status                   resolved => feedback
02-01-05 22:12 Mark Knecht    Resolution               not an issue => reopened
02-01-05 22:12 Mark Knecht    Note Added: 0003474                          
======================================================================




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