Re: [PATCH 3/3] nvme: Enable autonomous power state transitions

From: J Freyensee
Date: Fri Sep 02 2016 - 14:11:37 EST



> > >
> > >
> > > >
> > > > +ÂÂÂÂÂ/*
> > > > +ÂÂÂÂÂÂ* By default, allow up to 25ms of APST-induced
> > > > latency.ÂÂThis will
> > > > +ÂÂÂÂÂÂ* have no effect on non-APST supporting controllers
> > > > (i.e.
> > > > any
> > > > +ÂÂÂÂÂÂ* controller with APSTA == 0).
> > > > +ÂÂÂÂÂÂ*/
> > > > +ÂÂÂÂÂctrl->apst_max_latency_ns = 25000000;
> > >
> > > Is it possible to make that a #define please?
> >
> > I'll make it a module parameter as Keith suggested.
>
> One question, though: should we call this and the sysfs parameter
> apst_max_latency or should it be more generically
> power_save_max_latency?ÂÂThe idea is that we might want to support
> non-automonous transitions some day or even runtime D3.ÂÂOr maybe
> those should be separately configured if used.

I read the spec and reviewed your latest patchset. ÂPersonally for me I
like having the field names from the NVMe spec in the names of the
Linux implementation because it makes it easier to find and relate the
two. ÂSo apst_max_latency makes more sense to me, as this is a
'apst'(e/a) NVMe feature.

>
> --Andy
>
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