On Wed, Jan 04, 2017 at 08:57:47PM -0300, Javier Martinez Canillas wrote:
> Hello Doug,
>
> On 01/04/2017 06:05 PM, Doug Anderson wrote:
> > Hi,
> >
> > On Thu, Dec 29, 2016 at 6:17 AM, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> >> On Thu, Dec 15, 2016 at 04:54:30PM -0800, Doug Anderson wrote:
> >>>> Index: b/arch/arm/boot/dts/exynos5800.dtsi
> >>>> ===================================================================
> >>>> --- a/arch/arm/boot/dts/exynos5800.dtsi 2016-12-15 12:43:54.365955950 +0100
> >>>> +++ b/arch/arm/boot/dts/exynos5800.dtsi 2016-12-15 12:43:54.361955949 +0100
> >>>> @@ -24,6 +24,16 @@
> >>>> };
> >>>>
> >>>> &cluster_a15_opp_table {
> >>>> + opp@2000000000 {
> >>>> + opp-hz = /bits/ 64 <2000000000>;
> >>>> + opp-microvolt = <1250000>;
> >>>> + clock-latency-ns = <140000>;
> >>>> + };
> >>>> + opp@1900000000 {
> >>>> + opp-hz = /bits/ 64 <1900000000>;
> >>>> + opp-microvolt = <1250000>;
> >>>> + clock-latency-ns = <140000>;
> >>>> + };
> >>>
> >>> I don't think the voltages you listed are high enough for all peach pi
> >>> boards for A15 at 1.9 GHz and 2.0 GHz, at least based on the research
> >>> I did. See my response to v1.
> >>
> >> I wanted to apply this but saw this remaining issue. Javier tested it
> >> on Peach Pi so is this concern still valid?
> >
> > I'm not sure. It's been years since I did anything with exynos, so I
> > won't stand in the way if everyone else agrees that this patch is
> > good, but I will point out that testing on a single Peach Pi board is
> > not really enough given the massive difference in voltage needed
> > between the highest ASV group and the lowest (a whopping 112.5 mV from
> > looking in the Chrome OS source tree).
> >
>
> I agree. That's why answered that I wasn't able to find regressions on the
> Peach Pi I've access to, but I couldn't provide a Reviewed-by tag since it
> wasn't clear to me that the values were safe for any Exynos5420/5422/5800.
The value of 1.250 V seems to be covering only half of ASV values for
2.0 GHz so indeed it might be insufficient for some of the chips.
Unfortunately...
Best regards,
Krzysztof
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