Re: problem in changing from active to passive mode

[Rafael J. Wysocki]

On Thu, Oct 28, 2021 at 7:10 PM Julia Lawall <julia.lawall@xxxxxxxx> wrote:
>
> > Now, for your graph 3, are you saying this pseudo
> > code of the process is repeatable?:
> >
> > Power up the system, booting kernel 5.9
> > switch to passive/schedutil.
> > wait X minutes for system to settle
> > do benchmark, result ~13 seconds
> > re-boot to kernel 5.15-RC
> > switch to passive/schedutil.
> > wait X minutes for system to settle
> > do benchmark, result ~40 seconds
> > re-boot to kernel 5.9
> > switch to passive/schedutil.
> > wait X minutes for system to settle
> > do benchmark, result ~28 seconds
>
> In the first boot of 5.9, the des (desired?) field of the HWP_REQUEST
> register is 0 and in the second boot (after booting 5.15 and entering
> passive mode) it is 10.  I don't know though if this is a bug or a
> feature...

It looks like a bug.

I think that the desired value is not cleared on driver exit which
should happen.  Let me see if I can do a quick patch for that.