Hi - I've been trying for a while to ferret out the last persistent xruns in my Presonus Firebox/Kubuntu 11.04/jack/ardour2 setup, here.

The xruns are always about 700 or so ms. One every hour or so (min ~45m, max ~2 hours), regardless whether the computer is sitting idle or being heavily used (I can start three apps and have an eclipse build going, or be in a blank OpenBox session with only qjackctl and ardour2 going; it doesn't increase/decrease the frequency of xruns... my latency is at like 2 seconds while i try to solve the problem...)

It's looking like the X server is what is causing them... a variety of things are pointing to it (a script I use to log the output of top every .5 seconds, the fact that I can cause an xrun by selecting text in Firefox and dragging it around and I see the X process go to the top when the xrun happens, and the fact that an xrun happens when the screen blanks due to inactivity).

Lowering the priority of the X process and upping the niceness doesn't help. I'm pretty sure my other ducks are in a row (priorities, irqs, processes, groups, no CPU scaling happening, etc etc.) These exact xruns also happen with a vanilla install of Ubuntu Studio (with or without the lowlatency kernel in use).

Anyone have any idea how to tame the X server, or is this impossible to solve? Or maybe it's some other video or hardware issue? I feel like I'm so close...

It's a Dell Inspiron 6000 laptop. I'm using the default radeon driver, and I've seen some old threads about that maybe being an issue.

Thanks for any ideas! Excess info below.

-Casey

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I've actually been trying this more in Gnome because I get a lot less xruns, but I figure if I can sort out this issue it might enable me to get back to KDE, which I would greatly prefer.

In the process I've learned that ksysguard was causing a lot of xruns, and was able to make ksysguardd go away by removing all the system monitoring plasma widgets from my panel (temp, net traffic, CPU). That helped a lot, but I still get an xrun every 12 minutes or so in KDE... so I'm trying to stabilize in Gnome and hoping that can get me back home to KDE.

Exhaustive thread at: http://linuxmusicians.com/viewtopic.php ... 44&p=22391