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RE: Anyone success in ALSA driver for Delta 44?
- Subject: RE: Anyone success in ALSA driver for Delta 44?
- Date: Sat, 22 Feb 2003 12:57:31 +0100
> A program used (amixer, old fashion but good simple text mode) showed
> 96000 as below. The value was default of 48000 before I've made a change.
> # amixer -c 1 cset numid=42 12
> numid=42,iface=MIXER,name='Multi Track Internal Clock'
> ; type=ENUMERATED,access=rw---,values=1,items=14
> ; Item #0 '8000'
> ; Item #1 '9600'
> ; Item #2 '11025'
> ; Item #3 '12000'
> ; Item #4 '16000'
> ; Item #5 '22050'
> ; Item #6 '24000'
> ; Item #7 '32000'
> ; Item #8 '44100'
> ; Item #9 '48000'
> ; Item #10 '64000'
> ; Item #11 '88200'
> ; Item #12 '96000'
> ; Item #13 'IEC958 Input'
> : values=12 <=== here the result, set to Item #12 96000
> Note the last line of ": values=12" which indicates internal
> clock was changed
> to 96000. It WAS 48000 before I have made a change.
> This change was confirmed by another mixer program called alsamixer.
> I assume the term of "internal clock" is the speed we want.
We did the same. But if you run any sound application,
then look once more, the value is restored to 48000. That
is what we found out. I have no idea what is going on :-(
> OK, I got aumix here now and tried it but it looks there is no
> speed change
> Please try 'amixer' which has many options (too many):-(
> Maybe you are talking another mixer...
I do not have any computer with ALSA on it here.
> > So, should I wait for the release?
> >No, go on with the current version. When you have the Delta44 running
> >at 96kHz you will find that Linrad causes a lot of overrun errors
> >so the system becomes useless.
> ??? Do you mean above is the case OSS/not free or ALSA?
ALSA allocates smaller buffer space for the interrupt routines.
Linrad sets the fragment size for an interrupt rate of 25Hz
to minimize overhead. With ALSA there are then only 4 buffers in
total, Linrad sets the overrun error flag if the last buffer is
used, new data are arriving in the first buffer so there is only
one buffer, 40 milliseconds, allowed for processing between
reading the sound input. If you have a fast computer it may be ok.
I detected the problem on a slow computer that got overrun
errors already at 48kHz with ALSA. 00-54 allocates 8 buffers
for an interrupt rate of 50Hz so it will allow 5 buffers or
100 milliseconds between A/D reads.
> >Once you report this I will upload
> >00-54 immediately. If it takes some time I will wait. John, NI1B,
> >has a problem with all versions after 00-48, his system crashes
> >when he clicks on a signal on later versions. I would like to
> >have this corrected in 00-54 but there is not really any problem
> >to make an extra version if you need it.
> I don't have any problem with OSS driver 00-53a.
No. OSS allocates twice as much buffer space and you should not get
overrun errors unless cpu usage comes near 100%.
ALSA is supposed to save it's settings somewhere. Try to set 96000,
then reboot and see what speed the system comes up with. One way
or another it should be possible to have 96000 as the boot speed.
Once that works I would guess the speed will stay at 96000 when
Linrad is started.
Leif / SM5BSZ