Date: Mon, 13 Dec 2004 12:17:10 -0800 From: Nate Lawson <nate@root.org> To: "M. Warner Losh" <imp@bsdimp.com> Cc: rafan@infor.org Subject: Re: current powerstate and manually turn on/off? Message-ID: <41BDF8C6.4030607@root.org> In-Reply-To: <20041213.131052.42773193.imp@bsdimp.com> References: <20041213190604.GA81993@svm.csie.ntu.edu.tw> <20041213.121233.104111469.imp@harmony.village.org> <41BDF6A7.3040702@root.org> <20041213.131052.42773193.imp@bsdimp.com>
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M. Warner Losh wrote: > In message: <41BDF6A7.3040702@root.org> > Nate Lawson <nate@root.org> writes: > : Warner Losh wrote: > : >>By using sysctl, I do know what's the current powerstate > : >>of each device. I wounder is there any command or sysctl > : >>that can manually turn device on or off? > : > > : > > : > Not really, no. > : > : I think this is something the drivers should handle and we don't need to > : add user access to power states since it's probably the biggest way to > : shoot yourself in the foot. We already power down devices with no > : driver attached and once drivers get smart about powering down devices > : that are idle, this would cover all scenarios. > > It would be nice to have a way to say "This is a really strong hint > that you are now idle, go to lowest power, highest latency to get out > of it mode." I believe the driver itself has best knowledge of this, based on refcount, recent I/O, etc. You don't want the user turning off things without the driver's knowledge. -- Nate
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