Howdy Jeff,

Thanks for the info; have built and plugged my 3.5.0 OMAP-based kernel in to the Waterstorm. Things appear to work nicely, with a few curiosities.

1) the mpurate argument does not appear to be reflected in my BogoMIPS value; where historically (3.0-pm) I could set mpurate to 720 (on an Overo Water), and BogoMIPs would reflect the change (from 500 MHz), setting the mpurate parameter here results in my BogoMIPS sitting at ~600 still, but my 'cpuinfo_cur_freq' suggests things are currently clocked at 800 MHz.

2) Setting a rate of 600 as the mpurate again reflects correctly cpuinfo_cur_freq, but BogoMIPS shows up as 597 as usual.

3) Setting cpufreq via the userspace governor has the same effect as the previous two points.

I think I will contrive of a processor-intensive task so as to be sure things are actually changing somewhat...



On Sat, Feb 9, 2013 at 9:32 AM, Jeff DeFouw <> wrote:
On 2/7/2013 8:06 PM, Akram Hameed wrote:
> Just coming to terms with yocto and simultaneously testing out a Waterstorm I
> just received. One or two questions:
> 1) SoC in my WaterStorm is a DaVinci. When I set up my config for yocto I get
> a default machine of 'overo'. When I build things using the stable branch, I
> get a kernel (3.5.0) generated with CONFIG_ARCH_OMAP, rather than
> CONFIG_ARCH_DAVINCI, and all the associated OMAP stuff. Surely there should be
> an option for the DAVINCI stuff? I mean, I can manually edit my defconfig, but
> maybe I am missing the point here. I know things will work pretty much using
> an OMAP config, but they're not identical things...

I can't comment on the yocto and official overo build details, but
CONFIG_ARCH_DAVINCI is for an older DaVinci architecture.  The DM3730
architecture is very close to the OMAP3530.  A few runtime checks handle the

> 2) What is the recommended way to change cpu frequency in these newer kernels?
> I have, historically, used an mpurate arg to the kernel. Is this still OK, or
> should I be invoking a governor?

I've always used the userspace cpufreq governor and written to the
scaling_setspeed file in /sys.  mpurate should go through the same mechanism
if it still works.

Jeff DeFouw <>
Grand Rapids Technologies

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