Re: [PATCH 3/6] drm/msm/adreno: Allow specifying default speedbin value

[Konrad Dybcio]

On 4/9/24 20:04, Dmitry Baryshkov wrote:
> On Tue, Apr 09, 2024 at 10:12:00AM -0700, Rob Clark wrote:
> > On Tue, Apr 9, 2024 at 8:23 AM Dmitry Baryshkov
> > <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > > On Tue, Apr 09, 2024 at 05:12:46PM +0200, Konrad Dybcio wrote:
> > > > On 4/6/24 04:56, Dmitry Baryshkov wrote:
> > > > > On Fri, Apr 05, 2024 at 10:41:31AM +0200, Konrad Dybcio wrote:
> > > > > > From: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> > > > > >
> > > > > > Usually, speedbin 0 is the "super SKU", a.k.a the one which can clock
> > > > > > the highest. Falling back to it when things go wrong is largely
> > > > > > suboptimal, as more often than not, the top frequencies are not
> > > > > > supposed to work on other bins.
> > > > >
> > > > > Isn't it better to just return an error here instead of trying to guess
> > > > > which speedbin to use?
> > > >
> > > > Not sure. I'd rather better compatibility for e.g. booting up a new
> > > > laptop with just dt.
> > >
> > > New speedbin can have lower max speed, so by attempting to run it at
> > > higher freq you might be breaking it.
> >
> > Usually there are some OPPs in common to all speedbins, so picking a
> > freq from that set would seem like the safe thing to do
>
> Well, the issue is about an uknown speed bin. So in theory we know
> nothing about the set of speeds itsupports. My point is that we should
> simplfy fail in such case.

Or we could allow e.g. the lowest frequency (or 2) which if often shared
across the board to work, giving a compromise between OOBE and sanity

Konrad