Date: Mon, 13 Dec 2004 13:24:39 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: nate@root.org Cc: rafan@infor.org Subject: Re: current powerstate and manually turn on/off? Message-ID: <20041213.132439.41632908.imp@bsdimp.com> In-Reply-To: <41BDF8C6.4030607@root.org> References: <41BDF6A7.3040702@root.org> <20041213.131052.42773193.imp@bsdimp.com> <41BDF8C6.4030607@root.org>
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CYIn message: <41BDF8C6.4030607@root.org>
Nate Lawson <nate@root.org> writes:
: 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.
I agree. That's why I said 'strong hint' rather than 'command'.
Warner
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