Messages in this thread |  | | | From | Oliver Neukum <> | | Subject | Re: [RFD] Automatic suspend | | Date | Wed, 18 Feb 2009 16:05:15 +0100 |
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Am Wednesday 18 February 2009 15:51:58 schrieb Arjan van de Ven: > On Wed, 18 Feb 2009 09:53:48 +0100 > Oliver Neukum <oliver@neukum.org> wrote: > > > Am Wednesday 18 February 2009 00:26:53 schrieb Rafael J. Wysocki: > > > > Another possibility is to set up independent runtime PM for the > > > > transport and the device. This means allowing the possibility > > > > that the transport is suspended while its child (the device) is > > > > not. This is a little simpler (there's only one idle-timeout per > > > > device, since the link is treated as an independent device), but > > > > it violates the principle of never suspending a parent while > > > > there is an active child. > > > > > > Well, I think the first approach would be better. > > > > I am afraid it wouldn't be. How do you deal with shared transports? > > > > realistically, something like this you need to design like this > Step 1) Assume the hardware is smart and can do this for you on the fly, > but it might need guidance. > (For many busses there are platforms that do this) > Step 2) For hardware that is not smart, emulate the smartness in the > driver, with help of the subsystem. These two together have > the right knowledge to make such decisions.
But the transport and the driver may be in different subsystems, e.g. usb storage.
Regards Oliver
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