ac100 team mailing list archive

[Gordan Bobic <gordan@xxxxxxxxxx>]

On 08/20/2011 04:47 PM, Julian Andres Klode wrote:
> On Sat, Aug 20, 2011 at 04:33:17PM +0100, Gordan Bobic wrote:
> > On 08/20/2011 04:07 PM, Julian Andres Klode wrote:
> > > On Sat, Aug 20, 2011 at 03:31:56PM +0100, Gordan Bobic wrote:
> > > > Which kernel are you using?
> > >
> > > A somewhat older build of Marc's kernel (one month), the one
> > > I have in my Debian repository + the change to use 1000 instead
> > > of 1200.
> >
> > I presume you mean 1200mV rather than 1200MHz. If it's 1200MHz, I'd
> > like to know where to tweak that. ;)
>
> I never said anything of Hz. It's all mV (if it's mV, what are 1.2V
> used for? The voltage from the battery/charger is clearly 10-12V).
>
> > Well, my testing has been going on for 6+ hours. Considering I
> > couldn't get an hour without errors before (and sometimes
> > several/hour, and that's just the detected ones), I'd say it's a
> > very definitive improvement. So much so that I'm vaguely tempted to
> > try reducing it to 950mV. ;)
>
> Given that the minimum it currently scales to would be 725, 950
> is certainly save.

Seems there are limits in hardware. I built a kernel with the upper 
bound set to 900, and now I get a lot of this in the logs, while the CPU 
is stuck at 216MHz:

Failed to set dvfs regulator vdd_cpu
Failed to set regulator vdd_cpu for clock cpu to 875mV
cpu-tegra: Failed to set cpu frequency to 1000000kHz

over, and over and over.

Seems 975mV may be the lower limit, going to try that next.

Gordan