Underclocking the XO 1.5

Arne Babenhauserheide arne_bab at web.de
Thu Nov 29 12:11:09 EST 2012

Am Donnerstag, 29. November 2012, 16:35:42 schrieb James Cameron:
> On Tue, Nov 27, 2012 at 12:19:38PM +0100, Arne Babenhauserheide wrote:
> > I read the underclocking information on the custom bootloader page??
> > und wondered how to achieve the same with the 1.5, since the page
> > only gives the codes for the XO-1. How can I get the XO 1.5 to run
> > at the lowest possible CPU and Bus speed?
> You don't need to, it is automatic.
> You can get the XO-1.5 to run at the lowest possible CPU speed by
> running as few processes as possible, and writing your code to not
> waste CPU cycles.  The CPU will clock down to 400 MHz (1.5 W)
> automatically when demand is low.

I have other reasons for wanting it to always run at 400MHz (or as low as 

Normally I would set the governor to powersave, but I do not compile my own 
XO-Kernel, yet. 

It would be ideal to have a way to control this via the bootloader, so I can 
run the default kernel - or any kernel - just as I can do it with the XO-1.

> You can evaluate how successful this is with
> # cat /sys/devices/system/cpu/cpu0/cpuidle/state*/time
> or
> # cat /sys/devices/system/cpu/cpu0/cpuidle/state*/usage
> See Documentation/cpuidle in kernel source.
> Feel free to write this up on the Wiki.
> There's probably also other support in the kernel for manipulating
> the clocking, but I haven't identified it.

> > Does 1.5 support the under-/overclocking commands of 1.75, too?
> No.

OK, thanks!

Best wishes,
Ich hab' nichts zu verbergen – hab ich gedacht: 

- http://draketo.de/licht/lieder/ich-hab-nichts-zu-verbergen

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 316 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.laptop.org/pipermail/devel/attachments/20121129/4c9da940/attachment.sig>

More information about the Devel mailing list