[alsa-devel] Assert in pcm_params.c

[Takashi Iwai]

At Fri, 1 May 2015 08:36:47 +0100,
Alan Horstmann wrote:
> 
> On Monday 20 April 2015 12:17, Alan Horstmann wrote:
> > On Saturday 18 April 2015 09:08, Alan Horstmann wrote:
> > > The following assert is being hit in pcm_params.c:
> > >
> > > "pcm_params.c:2249: snd1_pcm_hw_params_slave: Assertion `err >= 0'
> > > failed."
> > >
> > > This is from a developer using Portaudio in his own application; I have
> > > yet to ascertain full details, but it is trying successive sample rates
> > > to see which are valid.
> >
> > Further info: this occurs with an Intel motherboard/soundcard, attempting
> > to open and config the stream at 44100 using front, surround or hdmi pcm,
> > having previously opened and tried at a lower, not-supported samplerate,
> > and closed. AFAIK other pcms work OK.
> >
> > The assert is hit with all current Debian and Ubuntu distros, for example
> >      Debian 8 (jessie) 32 bit:  kernel 3.16.0-4-686-pae (Alsa 1.0.28)
> > but is not seen with Fedora 20 or OpenSuse 12.1 (do they have asserts
> > off?).
> >
> > > Does this point to a flaw in the configuration or possibly a bug in
> > > Alsa-lib or can it occur just as a result of misuse of the Alsa API?
> >
> > I will try to conceive some more tests.  How can we debug this further?
> 
> A minimal self-contained demo program ('test-format') has been developed and 
> is attached, that demonstrates the issue 100% on the reporters machine 
> (HDA-Intel, 6-ch I believe).  The output is:
> 
> root at Xeon:/home/patest# ./test-format 
> Testing device front
> Num channels 6
> Testing rate: 22050   Result:...Invalid Sample Rate
> Testing rate: 32000   Result:...Invalid Sample Rate
> test-format: pcm_params.c:2249: snd1_pcm_hw_params_slave: Assertion `err >=
> 0' failed.
> Testing rate: 44100   Aborted
> 
> Alsa-info is at:
> 
> http://www.alsa-project.org/db/?f=19dfeee29f73007e61a00a8fabe3c958f7cb8e87
> 
> This apparently happens with or without Pulseaudio running, with just the 
> single 44100 rate, and also with surround devices.  Also, on all current 
> Debian and Ubuntu - we have focused on Jessie.
> 
> I do not have a machine with similar hardware, so cannot duplicate the 
> results.
> 
> Any comments, ideas etc would be appreciated.

I also can't reproduce this.  So this must be pretty specific to the
setup.

Could you give the exact condition to trigger the problem?  Also, this
happens certainly with the latest alsa-lib?


thanks,

Takashi