22 Nov
2005
22 Nov
'05
4:05 a.m.
Fernando,
Thanks very much for your help. I read the entire 5105 kernel bug
discussion and didn't find the valuable information you presented,
i.e. how to change the clocksource at runtime so easily. I was going
to try the "notsc" kernel option. For what it's worth I changed the
clocksource as you mentioned and I haven't had a glitch yet (10
minutes since the change).. and this is unusual.
Aaron
On 11/21/05, Fernando Lopez-Lezcano <nando(a)ccrma.stanford.edu> wrote:
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.
Which cpu
do you have?
I have AMD X2 also, the AMD X2 3800, interesting...
I have seen this coupled also to keyboard
repeats
being too fast because of kernel problems in keeping time (in my case
related to using AMD X2 dual core processors).
Really? well should I turn down
repeats in the BIOS or in Linux?
The X blackouts were actually the screensaver
kicking in. It is supposed to be fixed...
In which version is it supposed to be
fixed. I am using the latest
and greatest 2.6.14 plus the latest RT patch (rt13). The only thing I
don't quite understand is what to do with the post-release version
increments such as 2.6.14.2.. how do you patch that?
Which kernel are you running and do you have the same problem still?