Re: [RFD] How to tell ACPI drivers what the target sleep state is (was: Re: [PATCH 1/2] acpi choose sleep state help)

[David Brownell <david-b@pacbell.net>]

On Thursday 21 June 2007, Rafael J. Wysocki wrote:
> On Thursday, 21 June 2007 16:48, David Brownell wrote:

> > They really don't care what the state is.  The $SUBJECT patch isn't
> > driver code ... it's for platform hooks that expose attributes to
> > the drivers.  Specifically, it's ACPI code, talking to drivers that
> > must run on non-ACPI systems.  Any driver that thinks it needs to
> > understand anything about ACPI states is sadly broken.
> 
> But finally it has to place the device into a specific state and that state
> needs to be determined somehow. 

I suppose I'm still thinking that the approach in my original
patch works Just Fine.  Layering is kind of like this, going
from top to bottom (and omitting the go-to-pci-hardware stack,
and the initial ACPI pm hook before suspension starts):

	PM infrastructure ... calling suspend() for everything

	PCI bus support ... translates to PCI-specific typed call

	PCI driver ... suspend() calling pci_choose_state()

	ACPI support for PCI ... implementing choose_state()

	ACPI core code ... remembering ACPI_STATE_Sx, calling AML

That is, ACPI gets invoked at various points, but the driver and
core code doesn't need to know ACPI from Rumpelstiltskin.

- Dave