[LAU] Ardour 2.1 Mixer Levelmeters acting very slow with acpi=off

[Thomas Kuther]

On Mo, 19.11.07 10:46 susemuse27 at gmx.de wrote:

> hi,
> I should have known this earlier: when starting my 2.6.24.rc2-rt1
> with option "acpi=off" the audio performance increases significantly
> and I could be happy - but - the levelmeters in Ardour's Mixer are
> now acting strangely: They rise quickly but the falloff rate is at
> lowest level and can't be adjusted. I've tried with a different
> kernel, 2.6.23.1-rt11 - it's the same. Of course I can live with
> that, it doesn't prevent me from enjoying my musical activity, but it
> takes some patience... With acpi on action Ardour works fine. Did
> anybody make similar experience and can give me a hint where to start
> my  investigations? thanks Susanne
> 
> data:
> Asus Laptop AMD Athlon 64
> ATI-MobilityRadeon9700
> openSuse 10.2-32Bit
> USB-Lexicon Omega Studio
> Ardour built with VST-support
> 

Hi Susanne,

this sounds like a problem with the clocksource.
That could be caused by powernow-k8 and cpufrequency scaling.

I assume when the cpu is powered down right after startup, you see some
messages in dmesg saying:
------
Clocksource tsc unstable (delta = -107437170 ns)
------ 

If so, you could try to disable cpu frequency scaling
or make sure the system starts and runs with performance governor.

cat /sys/devices/system/clocksource/clocksource0/current_clocksource
shows the currently used clocksource. Please post the output of that
when booting with acpi=off and acpi enabled.


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