[LAU] xruns with m-audio fast track pro on fedora 8 ccrma

[Fernando Lopez-Lezcano]

On Tue, 2008-01-22 at 13:29 +0100, hitmuri at no-log.org wrote:
> Thanks for answering (maybe i could have asked on the linuxmao.org forum
> too ;) ) .
> 
> I tried to change the rtirq script but it doesn't seem to make any
> difference. But while looking at the rt priorities, i noticed that the
> highest priority for usb was given to the irq 16 and cat /proc/interrupts
> tells me that on irq 16 there's uhci_hcd:usb3 and NVIDIA !!!
> When i plug my usb soundcard , it's always on irq 20.
> So it looks like the highest priority is given to the graphics card .

Because it shares the interrupt with the usb controller which may have
an audio card attached...

What do you see in "cat /proc/interrupts" for other interrupts? Do you
perhaps have another usb controller that does not share an interrupt
with the graphics controller?

> Is this the problem to solve ?

It may be, hard to know for shure. 

-- Fernando


> > 2008/1/22, hitmuri at no-log.org <hitmuri at no-log.org>:
> >>
> >> Hi everyone,
> >>
> >> i have posted this on the planet ccrma list before, but i don't think
> >> it's
> >> a distribution problem. I get xruns when using a m-audio fast track pro
> >> usb soundcard  at 44100Hz, frames/period=64 (same with 128, i need low
> >> latency) ,periods/buffer=2 with my new laptop when i have for example
> >> freewheeling, tapeutape and jack-rack running (xruns seem to appear when
> >> the dsp load rises, i've got none when using tapeutape alone for
> >> example).
> >> Some of them were related to the latest ccrma kernel, and they
> >> disappeared
> >> with a previous one. For the other ones, i have 4 ideas :
> >>
> >> 1) latency timer :
> >> doing lspci, all the latencies show 0 , even when i set them to antoher
> >> value with setpci. But with dmesg, i can see that at startup they are
> >> set
> >> to 64.
> >> Fernando Lopez-Lezcano told me that on some hardware latency timer
> >> couldn't be changed and that 64 could be enough actually.
> >> (forgot to say that the usb irq isn't shared)
> >>
> >> So it looks like i can't do anything for that.
> >>
> >> 2) rtc :
> >> At startup i have a message from udev : Node Symlink... node /dev/rtc
> >> already exists , link to /dev/rtc0 will not overwrite it.
> >
> >
> >
> > I got this message too, but I don't know if there is any impact on the
> > sound
> > system.
> >
> > 3) soundcard power
> >> The fast track pro can be powered by usb or by an external power supply.
> >> Mine is usb powered for now. Is this a problem ?
> >>
> >> 4) rtirq
> >> I noticed that in the rtirq script , i have these lines:
> >> RTIRQ_NAME_LIST="rtc snd usb i8042"
> >> RTIRQ_NON_THREADED="rtc snd"
> >> Do they need to be changed when using a usb soundcard ?
> >
> >
> > If your sound card works with USB, you can write this :
> >
> > RTIRQ_NAME_LIST="rtc usb i8042"
> > RTIRQ_NON_THREADED="rtc usb"
> >
> >
> > Then you restart the script  and echo his status
> >
> > $ sudo /etc/init.d/rtirq restart
> > $ /etc/init.d/rtirq status
> >
> > You will see the priority on each IRQ. Then you have to connect your sound
> > card on the USB port wich has the best priority.
> >
> >
> > If anyone has an idea on that...
> >>
> >> Sorry it was quite long !!
> >>
> >> Thanks
> >>
> >> Flo
> >
> >
> > Hope this help you,
> > cheers,
> >
> > Mysth-R
> >
> >
> > --
> > *
> > ***************************************************************************************
> > *  {^_^} Mysth-R {^_^}
> > *
> > * http://myspace.com/mysthr
> > * http://myspace.com/aideauditive
> > * http://mysthr.free.fr  => Site dédié à l'audio sous Fedora/PlanetCCRMA.
> > *
> > ***************************************************************************************
> >
> 
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