Messages in this thread |  | | Date | Thu, 18 Oct 2001 10:38:08 -0700 (PDT) | From | Patrick Mochel <> | Subject | Re: [RFC] New Driver Model for 2.5 |
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On Thu, 18 Oct 2001, Jonathan Lundell wrote:
> At 11:08 AM -0500 10/18/01, Taral wrote: > >On Wed, Oct 17, 2001 at 04:52:29PM -0700, Patrick Mochel wrote: > >> When a suspend transition is triggered, the device tree is walked first to > >> save the state of all the devices in the system. Once this is complete, the > >> saved state, now residing in memory, can be written to some non-volatile > >> location, like a disk partition or network location. > >> > >> The device tree is then walked again to suspend all of the devices. This > >> guarantees that the device controlling the location to write the state is > >> still powered on while you have a snapshot of the system state. > > > >Aha! A much nicer solution to the problem the ACPI people are having > >with suspend/resume (ordering problems). > > What happens to state changes between the first and second traversal > of the device tree?
State changes of what?
After the first walk (save_state), you essentially have a snapshot of the system in memory which can be written to disk, memory, etc.
Once that is done, you disable interrupts and walk the tree again to power off devices.
-pat
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