[LAU] real time audio and graphic/ interrupt tweaks?

david gnome at hawaii.rr.com
Mon Jul 27 03:48:31 EDT 2009

Arnold Krille wrote:
> On Monday 27 July 2009 01:36:57 Martin Horn wrote:
>> I try to run xwax on ubuntustudio 8.10 on a Panasonic CF-T2 subnotebook
>> (1Ghz/512MB). Everytime I start real time audio apps like jack the graphic
>> gets very slow and freezes for some seconds, also the audio playback is
>> like timestretched and sounds filtered.
>> I guess it has something to do with interrupts shared by graphic and sound
>> (sound comes from a Maya44 USB sound card).
>> Can anybody give me a hint how to check or alter interrupt settings or do
>> you have any other ideas...?!
> Most computers have more then one usb port. And these usb ports sit on 
> different irq's, I doubt it that all of them are shared with the graphics.

Well, if the OP has an Intel chipset - practically everything could be 
sharing an interrupt with the graphics. ;-)

More important to know which internal HUB the laptop's USB ports are 
hooked to. My Toshiba laptop has 3 USB ports but only 2 USB internal 
hubs ...

> How do you know which usb port uses which irq?
> Check the output of "lsusb" and "cat /proc/interrupts" to see where you audio-
> device is connected and which irq that port has.

I had similar-sounding problems with my UCA202 USB sound card when I was 
running it as USB device #7 on a powered external 7-port USB2 hub. 
Problem went away when I hooked it directly to a port on the laptop.

gnome at hawaii.rr.com
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