[linux-audio-user] USX2Y rawusb mode

[Spencer Russell]

OK, So as per these several suggestions, I've now tried the US428
with a vanilla 2.6.11, a 2.6.11 with Ingo's preempt patch and
full preemption, nrpacks=4, apm and acpi not compiled in the
kernel, and without my usb ethernet card plugged in. I'm still
getting the "Sequence Error!" messages, then a couple seconds
later qjackctl dissapears.

I still haven't tuned the IRQ stuff, because I'm still getting
the error of:

execvp: No such file or directory
failed to execute pidof "IRQ 8"

when I try to execute chrt -f -p 80 'pidof "IRQ 8"' I'm not sure what do do
about that one, and google and man don't seem to help me much. Any thoughts?
Thanks,
-spencer


On Thu, Mar 03, 2005 at 06:58:08PM +0100, Karsten Wiese wrote:
> Am Donnerstag 03 M?rz 2005 16:32 schrieb Spencer Russell:
> > On Thu, Mar 03, 2005 at 12:41:17PM +0100, Karsten Wiese wrote:
> > >  
> > > can you check if this error doesn't happen, when modprobing like 
> > > 	$ modprobe snd_usb_usx2y nrpacks=4
> > > ?
> > > nrpacks=1 and "rawusb mode" are irrelevant if you run jack with moderate latencies
> > > as above "-p1024 -n2" and 2 inputs.
> > > 
> > 
> > With nrpacks=4, it seems to last slightly longer before giving
> > the "Sequence Error!" and "Most propably some urb of usb-frame
> > 935 is still missing"
> > 
> 
> try with apm and acpi disabled.
> append "apm=off acpi=off" to the kernels boot parameter line.
> on laptops lots of things happen "beghind the scenes" .
> "apm=off acpi=off" made a big differenc here when I used 2.4 kernels.
> 
> > > What kernel are you using? If its not 2.6.11 you might give that a try.
> > 
> > Every time I've tried using a 2.6 kernel on this machine, I get
> > these random lockups that I can't figure out, so I'm using 2.4.26
> > with lowlatency, preempt, and givecap patches. I'll try 2.6.11,
> > and see how that goes.
> 
> also on 2.6.11 you'd disable apm & acpi like above to try to get rid 
> of those random lockups or "Sequence Error!"s.
> 
> > 
> > Rui said a while ago that he was getting a similar message, until
> > he tuned the IRQ priorities, but I've been googling around and I
> > can't figure out how to do it. I tried
> > chrt -f -p 90 'pidof "IRQ 0"'
> > as directed on some website, but it just returns
> > 
> > execvp: No such file or directory
> > failed to execute pidof "IRQ 0"
> 
> this is for the realtime kernel patches by Ingo Molnar.
> I may be wrong, but I'd suggest you get it running on 2.6.11 before you
> proceed with the realtime kernels.
> Plain 2.6.11 gives me better low latency (and better behavior with acpi enabled too) than
> patched 2.4 kernels. lots of Ingo's enhancements are in 2.6.11 already.
> 
> Still the very basic mode with 
>  	$ modprobe snd_usb_usx2y nrpacks=4
> must work flawlessly with  2 in / 2 out jack like
> 	$ jackd -R -dalsa -dhw:0
> on a plain kernel as first step.
> 
> 
> > srussell at slingshot:~$ lsusb
> > Bus 001 Device 001: ID 0000:0000  
> > Bus 001 Device 002: ID 07a6:0986 ADMtek, Inc. AN986 Pegasus Ethernet
> > Bus 001 Device 005: ID 1604:8001 Tascam US-428 Audio/Midi Controller
> 
> Your ethernet is also on usb!
> Usb audio is enough to fully occupy an USB 1.1 bus.
> Try with us428 as the only usb client (without that usb ethernet).
> 
> cheers
> Karsten
> 
>