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Message-ID: <1472839879.2754.77.camel@linux.intel.com>
Subject: Re: [PATCH 3/3] nvme: Enable autonomous power state transitions
From: J Freyensee <james_p_freyensee@linux.intel.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>,
        Christoph Hellwig <hch@lst.de>, linux-nvme@lists.infradead.org,
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Date: Fri, 02 Sep 2016 11:11:19 -0700
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> > > 
> > > 
> > > > 
> > > > +     /*
> > > > +      * By default, allow up to 25ms of APST-induced
> > > > latency.  This will
> > > > +      * have no effect on non-APST supporting controllers
> > > > (i.e.
> > > > any
> > > > +      * controller with APSTA == 0).
> > > > +      */
> > > > +     ctrl->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?  The idea is that we might want to support
> non-automonous transitions some day or even runtime D3.  Or maybe
> those should be separately configured if used.

I read the spec and reviewed your latest patchset.  Personally 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.  So apst_max_latency makes more sense to me, as this is a
'apst'(e/a) NVMe feature.

> 
> --Andy
> 
> _______________________________________________
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> http://lists.infradead.org/mailman/listinfo/linux-nvme