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@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?
It can be reproduced by modify snd-dummy to use azx_pcm_hw
6 channels and softvol similar to hda controller which support arbitrary period size
snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 4);
snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);
https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/pc...
Slave can return err when call schange
snd_pcm_hw_params_t slave_params; int err; err = sprepare(pcm, &slave_params); assert(err >= 0); err = schange(pcm, params, &slave_params); - assert(err >= 0); + if (err < 0) + return err; err = sparams(pcm, &slave_params); if (err < 0) cchange(pcm, params, &slave_params); return err;