Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [RFD] Automatic suspend | Date | Mon, 16 Feb 2009 23:12:48 +0100 |
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On Monday 16 February 2009, Arjan van de Ven wrote: > On Mon, 16 Feb 2009 22:48:32 +0100 > "Rafael J. Wysocki" <rjw@sisk.pl> wrote: > > > > Userland should never ever control the state of a device like this > > > directly. It should do so by a) closing the device and b) setting > > > latency / functional requirements. > > > > The user, however, may want to forcibly put a device into a low power > > state without stopping all of the applications that depend on it (eg. > > have it open). Do you think that we shouldn't allow users to do such > > things? > > I would think that that is a bad mistake to do. It basically breaks the > contract that the kernel has with userspace....
OK, so I think there are two things that user space may be allowed to do as far as putting devices into low power states is concerned: * disable/enable the automatic power management of the device (provided that the driver supports the automatic PM) * check what power states devices are in.
Thanks, Rafael
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