Re: [RFC][PATCH 1/1]nand/denali: Add runtime pm support for denali controller driver

[Arjan van de Ven <arjan@infradead.org>]

On Tue, 7 Sep 2010 12:03:40 +0800
"Dong, Chuanxiao" <chuanxiao.dong@intel.com> wrote:

> 
> > if you take the refcount every time you get a command, and drop a
> > count each time a command completes.... this is all not too
> > important.. it'll just work
> If I take the refcount every time I got a command and drop a count
> each time a command completes, the controller device will be resumed
> every time when it gets a command and suspended after it finishes a
> command. For a 4k page NAND, processing just 1M data will cause
> device resume/suspend 256 times....This will influence the
> performance...

so this is where you can tell the runtime PM system to use a timer, and
only turn on power saving after some idle time.

you don't need to do that yourself... the runtime PM system has this
capability built in!


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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