Re: [PATCH V3 2/2] base/drivers/arch_topology: Default dmips-mhz if they are not set in DT

From: Quentin Perret
Date: Mon Nov 26 2018 - 07:15:47 EST


On Monday 26 Nov 2018 at 12:36:31 (+0100), Daniel Lezcano wrote:
> On 26/11/2018 12:09, Quentin Perret wrote:
> > On Monday 26 Nov 2018 at 15:49:55 (+0530), Viresh Kumar wrote:
> >> On 26-11-18, 11:08, Daniel Lezcano wrote:
> >>> On 26/11/2018 10:52, Quentin Perret wrote:
> >>>> Maybe you want to test 'if (!raw_capacity || cap_parsing_failed)' at the
> >>>> top of topology_parse_cpu_capacity() ?
> >>>
> >>> I prefer to update the documentation, it makes more sense than adding
> >>> more cumbersome tests in the current code.
> >>
> >> +1
> >>
> >> Throwing an error and ignoring DT number completely for the capacity
> >> are good enough in my opinion as well.
> >>
> >> And who cares for the platforms that can't even fill the DT properly :)
> >
> > Right, I think we all agree the case with a partially filled DT is
> > broken. I don't actually care too much about the behaviour in this case,
> > but it needs to be consistent with the doc.
> >
> > So, as long as you fix the doc, that change is fine by me :-)
>
> Ok what about the following change ?
>
> "
>
> If capacity-dmips-mhz is not specified or if the parsing fails, the
> default capacity value will be computed against the highest frequency,
> it will result most of the time on the same capacity value.

That "most of the time" sounds a bit odd no ? Maybe mention explicitly
the case you're referring to (that is when all CPUs have the same max
freq) ?

> However on
> some platform with different OPP set but the same micro-architecture,
> the capacity will be scaled down for CPUs having lower frequencies.
>
> "

Other than that LGTM.

Thanks,
Quentin