Re: Nokia N900: Proper C-states

[Daniel Lezcano]

On 02/09/2016 04:56 PM, Tony Lindgren wrote:
> * Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> [160102 14:01]:
> > On 01/02/2016 03:26 PM, Pali RohÃr wrote:
> > > Hello,
> > >
> > > due to this Daniel Lezcano commit (ARM: OMAP3: cpuidle - remove rx51
> > > cpuidle parameters table)
> > >
> > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=231900afba52d6faddfb480cde4132d4edc089bc
> > >
> > > we need patch cpuidle34xx.c code to fix commit for Nokia N900. See:
> > >
> > > https://github.com/pali/linux-n900/commit/e147fd4b678f1f3d7a5235287910960bd41e04dc
> > >
> > > As Nokia N900 code is converting from legacy board code to DST, I would
> > > like to know how to patch correctly omap3_idle_driver in DTS with
> > > correct values measured for Nokia N900. Thanks!
>
> I'm almost certain those values are not n900 specific but should be
> used for omap3430 in general.
>
> > the conversion to the DT based arm cpuidle driver could be a bit complex
> > with one issue (index 0 != cpu_do_idle()) and one performance regression
> > (cpu_pm_enter/exit will be called in retention mode, even if this is not
> > needed).
> >
> > It will result in a PM code only on one side and on the other side, the
> > generic cpuidle-arm.c driver will be used instead with the DT definition. It
> > is worth to the conversion because the result will be nice IMO.
> >
> > Added Lorenzo who is initially author of the arm generic driver. We already
> > discussed in the past about those two issues above and I think this is
> > something we should improve.
>
> While this conversion process is going on, we could just add
> omap3430_idle_driver and set that based on cpu_is_omap3430()
> in omap3_idle_init().

Yes, that could be a temporary alternative.




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