Help: Mystified with ALSA+Jack..(almost there)..
 

I made it quite far already but I'm confused
about what remains to be done.

I've already build a fine LFS 6.2.
My hardware is SB Live 24bit, and my Kernel
is cmpiled fine for it. I also have an
onboard ICH5 Intel sound device. All detected.

I've compiled JACK and installed.
I've compiled ALSA libs tools and plugins.

/dev/snd has the entries:
controlC0 and C1
midiC1D0
pcmC0D0c
pcmC0D0p
pcmC0D1c
pcmC0D1p
.
.
.
seq
timer

When I type:.. I get:
#aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0:ICH5 [Intel ICH5], device 0: Intel ..blablabla.
Subdevice: 1/1
Subdevice #0: subdevice #0
card :ICH5 [Intel ICH5], device 4: Intel ICH -IEC958 [Intel ....]
Subdevice: 1/1
Subdevice #0: subdevice #0
card 1:CA0106 [CA0106],device 0: ca0106 [CA0106]
Subdevice: 1/1
Subdevice #0: subdevice #0
card 1:CA0106 [CA0106],device 1: ca0106 [CA0106]
Subdevice: 1/1
Subdevice #0: subdevice #0
card 1:CA0106 [CA0106],device 2: ca0106 [CA0106]
Subdevice: 1/1
Subdevice #0: subdevice #0
card 1:CA0106 [CA0106],device 3: ca0106 [CA0106]
Subdevice: 1/1
Subdevice #0: subdevice #0
----
I'm interested in using the CA0106, which is
the SB Live 24bits.

I also have:
/proc/asound/CA0106/
/proc/asound/ICH5/
/proc/asound/card0/
/proc/asound/card1/
/proc/asound/oss/
/proc/asound/seq/
/proc/asound/cards
/proc/asound/devices
/proc/asound/pcm
/proc/asound/timers
/proc/asound/version

MY PANIC is that I don't know how to setup
ALSA to use JACK; Or is it JACK using ALSA ??
I'm confused. Am I right to think I have to
start some sort of JACK deamon first,
(jackd -v -d alsa (card???) -r44100 ?????
and
then give ALSA some kind of 'pcm' config file.
Is it the other way around ?
I'm really confused.
--
P.S.
I'll be happy when I can successfully run the
JACK example-clients like:
jackrec*
(I presume this allows me to record a timed WAV file)
And yes, the asound library is there ready..
I'm just quite lost with the setup.

Thanks in advance.

FOLLOW-UP:

Without doing anything to my configuration.
Remember this is no Mandrake or Suze, it`s a plain
vanilla Linux From Scratch (LFS) to which I am
growing sound support. My purpose is not tu run
under Xwindows, so I'm not installing the more advanced
tools often used to ease the pain..

So, I just tried to start 'jackd' from the prompt:

#jackd -v -d alsa ca0106 -r44100 2>/mnt/floppy/test

Then I CTRL-C to stop it and see.. Here is test file:
(I think it`s promising) :D

getting driver descriptor from /usr/lib/jack/jack_alsa.so
getting driver descriptor from /usr/lib/jack/jack_dummy.so
getting driver descriptor from /usr/lib/jack/jack_oss.so
JACK compiled with System V SHM support.
server `default' registered
registered builtin port type 32 bit float mono audio
loading driver ..
new client: alsa_pcm, id = 1 type 1 @ 0x80578d0 fd = -1
apparent rate = 44100
configuring for 44100Hz, period = 1024 frames, buffer = 2 periods
Note: audio device hw:0 doesn't support a 32bit sample format so JACK will try a 24bit format instead
Note: audio device hw:0 doesn't support a 24bit sample format so JACK will try a 16bit format instead
nperiods = 2 for capture
nperiods = 2 for playback
new buffer size 1024
registered port alsa_pcm:capture_1, offset = 4096
registered port alsa_pcm:capture_2, offset = 8192
registered port alsa_pcm:playback_1, offset = 0
registered port alsa_pcm:playback_2, offset = 0
registered port alsa_pcm:playback_3, offset = 0
registered port alsa_pcm:playback_4, offset = 0
registered port alsa_pcm:playback_5, offset = 0
registered port alsa_pcm:playback_6, offset = 0
++ jack_rechain_graph():
client alsa_pcm: internal client, execution_order=0.
-- jack_rechain_graph()
2064 waiting for signals
load = 0.0070 max usecs: 3.000, spare = 21330.000
load = 0.0105 max usecs: 3.000, spare = 21330.000
load = 0.0123 max usecs: 3.000, spare = 21330.000
jack main caught signal 2
starting server engine shutdown
stopping driver
unloading driver
freeing shared port segments
stopping server thread
last xrun delay: 0.000 usecs
max delay reported by backend: 0.000 usecs
freeing engine shared memory
max usecs: 3.000, engine deleted
no message buffer overruns
cleaning up shared memory
cleaning up files
unregistering server `default'
-------

Okay,, So the line above:
"jack main caught signal 2"
Probably came when I've hit CTRL-C to stop this fg task.

Now I guess I have to fiddle with a proper alsa ~/.asoundrc
????
Thanks in advance for any tips.

alsa and jack
 

I am hardly an expert on sound, but I did just get jackd working, and can tell you a few thins hoepfulyl helpful.

ALSA drives the sound hardware; you can think of Jack as a higher-level service, that provides sound connectivity services to sound applications (patching app A to app B, etc) and uses ALSA to output (and input) sound.

When Jack is used, sound apps (xmms, whatever) no longer talk to ALSA; they talk to Jack. Jack adds a layer of sound-service abstraction above ALSA.

If all you want to do is have single apps output sound (xmms, mplayer, etc) skip installing Jack -- not only is it not necessary it's a major PITA to get running, but worth it if you intend to make music, DJ, etc. It requires the use of a low-latency kernel. Skip Jack unless you intend to do high-end audio stuff like mixing or live performance.

When Jack is running sound apps can no longer talk to ALSA; Jack owns it.

You must first get alsa to work.

good U done well