Re: [linux-audio-user] intermittent X blackout in rt kernel

On Mon, 2005-11-21 at 15:25 -0500, Aaron Phillips wrote: I still have the problem and it is not fixed yet (just earlier today I think I finally understood what is actually happening). At this point this only happens on dual core systems (for example the Athlon X2 processor family) running an SMP i386 kernel, it does not happen on x86_64 systems. A patch has just been posted to lkml (by John Stultz) that should take care of this, but it will take a while for the stuff to get to the -rtxx patches. There is a workaround (thanks to John Stultz) which is to change the source clock for the timing to something other than the TSC[*]. You can see which source is being used by typing: cat /sys/devices/system/clocksource/clocksource0/clocksource The default should show something like this: acpi_pm jiffies *tsc pit note the "*" next to tsc, means it is the one being used. If you have acpi_pm change the source to it like this: echo "acpi_pm">/sys/devices/system/clocksource/clocksource0/clocksource That should fix the problem you are having. You can also add "clocksource=xyz" as a boot time kernel parameter, where xyz is the source you want to use. -- Fernando [*] "Time Stamp Clock": on Athlon X2 systems each cpu has its own and they can drift from each other, software that does not take this into account gets into big trouble, for example Jack.