Re: Avoid C2/C3 idle state

Dominik Brodowski
2009-11-24T22:29:50Z

Hey,

you can set the maximum C-state to use using the
"processor.max_cstate=<value>" parameter. No need to recompile.

Best,
Dominik

On Tue, Nov 24, 2009 at 09:50:01PM +0000, Alex wrote:
> I run Ubuntu 8.04.3 LTS server 32bit in a small low power motherboard (VIA LN10000EG) equipped with VIA C7 1GHz CPU.
> Kernel 2.6.24
>
> I've some problems with serial device: sometimes I've overrun errors when receive data through /dev/ttyS0
>
> After some days of hard work I've discovered that when CPU enter in C2 or C3 state and data come in from serial line, I've the overrun.
>
> I've searched for a solution and I've found that kernel parameter "idle=halt" can avoid CPU enter C2/C3 state, but this parameter is now not supported anymore (it was in the past).
> So I've completely disabled the ACPI support ("acpi=off" kernel parameter).
> But I lack support for power button, poweroff command and so on.
> I wish to re-enable ACPI.
>
> The question is: Howto avoid CPU enter C2/C3 state and re-activate ACPI so CPU can go in C1 state ? C1 is better than nothing at all ....
>
> I have no problem to modify kernel source and recompile it.
>
> Thanks fo suggestions
>
>
>
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