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

2008/1/22, hitmuri@email-addr-hidden-log.org <hitmuri@email-addr-hidden-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

-- 
*
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*  {^_^} Mysth-R {^_^}
*
* http://myspace.com/mysthr
* http://myspace.com/aideauditive
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Received on Tue Jan 22 16:15:02 2008