Re: [PATCH V2] arm64: dts: qcom: sc7280: Add nodes for eMMC and SD card

[Doug Anderson]

Hi,

On Thu, Mar 25, 2021 at 11:57 PM <sbhanu@xxxxxxxxxxxxxx> wrote:
>
> >>> +                       max-frequency = <192000000>;
> >> Why do you need to specify this?
> This helps to avoid lower speed modes running in high clock rate,
> and As Veerabhadrarao Badiganti mentioned

Just to be clear, both Stephen and I agree that you should remove
"max-frequency" here (see previous discussion). Bjorn is, of course,
the file decision maker. However, unless he says "yeah, totally keep
it in" I'd suggest dropping it from the next version.


> >>> +                                       required-opps =
> >>> <&rpmhpd_opp_low_svs>;
> >>> +                                       opp-peak-kBps = <1200000
> >>> 76000>;
> >>> +                                       opp-avg-kBps = <1200000
> >>> 50000>;
> >> Why are the kBps numbers so vastly different than the ones on sc7180
> >> for the same OPP point. That implies:
> >>
> >> a) sc7180 is wrong.
> >>
> >> b) This patch is wrong.
> >>
> >> c) The numbers are essentially random and don't really matter.
> >>
> >> Can you identify which of a), b), or c) is correct, or propose an
> >> alternate explanation of the difference?
> >>
>
> We calculated bus votes values for both sc7180 and sc7280 with ICB tool,
> above mentioned values we got for sc7280.

I don't know what an ICB tool is. Please clarify.

Also: just because a tool spits out numbers that doesn't mean it's
correct. Presumably the tool could be wrong or incorrectly configured.
We need to understand why these numbers are different.

-Doug