[PATCH/RFC v2 0/2] CPUFreq for kzm9g

Guennadi Liakhovetski g.liakhovetski at gmx.de
Fri Mar 1 16:11:41 EST 2013

On Tue, 26 Feb 2013, Magnus Damm wrote:

> On Tue, Feb 26, 2013 at 2:16 AM, Guennadi Liakhovetski
> <g.liakhovetski at gmx.de> wrote:
> > In v2 of this patch-set I dropped patches 1 and 3, because #1 is a bug-fix
> > and can go in separately, #3 is more of a debugging help, than a real
> > patch for mainlining. Of the remaining 2 patches the main difference to v1
> > is the omission of the PLL0 manipulation. More is explained in respective
> > patches.
> >
> > Guennadi Liakhovetski (2):
> >   ARM: shmobile: sh73a0: add support for adjusting CPU frequency
> >   ARM: shmobile: kzm9g-reference: add CPUFreq support
> Hi Guennadi,
> Thanks for your work on this. In general I am quite happy about this series.
> One rather significant question is however this: Would it be possible
> for you to check if the TWD is operating as expected when you scale
> the CPU Frequency? I suspect it is not, so please cook up a v3 of this
> series that also includes updates for timers.

At last I managed to get twd running with a recent (of 27.02) all+next 
snapshot on kzm9g with DT (reference) and actually I'm not really sure the 
problem is there. At least definitely not as bad as I saw it last time. To 
remind, the problem I observed was, that at lower CPU speeds a simple 
shell script, consisting of 20 20-second sleep calls was gaining multiple 
seconds, was taking more like 405 seconds, than 400. Now I only see it 
going to 401 seconds. This is still not good, but I need a more precise 
comparison to actually decide, whether this problem only appears at lower 
CPU speeds or it is always there. I'll look further into it next week.

Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer

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