[alsa-devel] twl4030 and Puredata/jack

[Anders Alex]

Ok,

Let me start off that I know very little about audio and drivers.

Recently I started looking in to running Puredata and possibly jack on the
Pandora handheld.
However I ran in to a number of problems getting these to interface with
alsa.
I should note that on the pandora we don't have too up to date versions of
alsa and kernel so perhaps these are already resolved.
In SL4P (slackware for pandora) I have:

ALSA: 1.0.24
Kernel: 3.2.30

I will paste a couple of use-cases and their corresponding dmesg output:

When I run ~$ pd -alsa I get:

snd_pcm_hw_params (input): Invalid argument
snd_pcm_hw_params (output): Invalid argument

and:
[201429.385345] omap_mcbsp_dai_hw_params: not enough bandwidth for desired
rate and channels
[201429.385375] asoc: interface omap-mcbsp-dai.1 hw params failed

With 'jackd -d alsa -S'  (need s16_le):

loading driver ..
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|16bit
control device hw:0
configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 16bit little-endian
ALSA: use 2 periods for capture
ALSA: cannot set hardware parameters for capture
ALSA: cannot configure capture channel


cannot load driver module alsa

and:
[201746.759857] asoc: can't set codec twl4030-hifi hw params

The pandora kernel-dev explained that the hardware can only handle stereo
streams. However someone in #jack explains it as the following:
"This typically means that the ALSA driver is incomplete or buggy when used
the way JACK does (poll+mmap) vs. the way aplay does (blocking read+write).
So things that do stuff the "aplay way" will work; things that do stuff the
JACK way will not work."

I hope someone can shed some light on this and perhaps give some ideas to
how to get this working.

cheers,
alexander