frequency scaling on D525MW not working properly

Sven Gaerner sgaerner at
Mon Jul 23 12:24:38 PDT 2012

On Mon, Jul 23, 2012 at 09:44:06AM +0800, Sepherosa Ziehau wrote:
> On Mon, Jul 23, 2012 at 3:27 AM, Sascha Wildner <saw at> wrote:
> > On Sun, 22 Jul 2012 21:16:54 +0200, Sven Gaerner <sgaerner at> wrote:
> >
> >> On Sun, Jul 22, 2012 at 08:31:41PM +0200, Sascha Wildner wrote:
> >>>
> >>> On Sun, 22 Jul 2012 13:46:41 +0200, Sven Gaerner <sgaerner at>
> >>> wrote:
> >>>
> >>> >[...]
> Hmm, disabling UEFI is OK, but make sure that you have enabled EST in
> BIOS (something probably read like "enhanced speed step" or something
> like "P-state").
There is no such option. And the only UEFI option is to enable booting
of an UEFI compliant OS. Speed stepping cannot be configured. The BIOS
options are very limited.

> Besides CPU P-State, you could also set allowable CPU C-State to C3 by
> setting sysctl hw.acpi.cpu.cx_lowest and put tunable
> hw.i8254.intr_disable="0" in /boot/loader.conf (you need to reboot
> after changing /boot/loader.conf).  However, it should be noted that
> enabling C3 will disable LAPIC timer and i8254 timer will be used
> instead, which may cause extra overhead.
This seems not to change anything. The temperature remains the same. And
setting hw.acpi.cpu.cx_lowest returns with "Invalid Argument".

Updating the BIOS to a more recent version did also not help.

Thanks for your hints.


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