ac100 team mailing list archive

[Gordan Bobic <gordan@xxxxxxxxxx>]

On 08/21/2011 11:49 AM, Julian Andres Klode wrote:
> On Sat, Aug 20, 2011 at 05:27:18PM +0100, Gordan Bobic wrote:
> > On 08/20/2011 05:25 PM, Gordan Bobic wrote:
> > > 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
> >
> > ^^^^^^^^^^^^^^^^
> > This should have read 975mV
> >
> > > cpu-tegra: Failed to set cpu frequency to 1000000kHz
> > >
> > > over, and over and over.
>
> I get the same problem when setting SM1 to a maximum of 1000mV,
> because dvfs tries to set it to 1100 mV, which fails. And
> extreme instability.

Really? It complains about a max of 1000mV? On my AC100 975mV and above 
produces no error. What model did you say you have?

> Harmony sets minimum voltage to 750 and maximum voltage to 1125,
> maybe that gives more stability?

Interesting. It also occurs to me that just tweaking voltages (which, 
again, would be much easier if they were run-time adjustable via /sys as 
I said in a previous post), it would be really handy to get core 
temperature readings? Does the AC100 have temperature sensors built in?


On an unrelated note, I noticed an interesting possible correlation of 
an error in my message log with instability that I am currently 
investigating. It is possible that I have been barking up a completely 
wrong tree so far. I need to do some more investigating (A _LOT_ of SLUB 
memory allocation failures, possibly to do with zram swapping and/or the 
size of vmalloc set on the kernel command line).

Gordan