On Fri, Jan 20, 2006 at 07:50:45AM +0100, Karol Kozimor wrote:
> Thus wrote Adam Belay:
> > > Note also that there are very few explicit calls to pci_enable_wake() in
> > > the whole tree. Linux doesn't set the PME-Enable bit properly, which
> > > apparently results in WOL either working or not working. My understanding
> > > is that the final outcome depends on what BIOS does to the card during
> > > POST. Please see http://bugme.osdl.org/show_bug.cgi?id=3801 for a weird
> > > example.
> > I'm in the process of overhauling the PCI layer's power management event
> > support. Basically, I'd like to catch ACPI GPE events and then walk the
> > device tree in thier corresponding location to see if PME is set. If so
>
> Ouch. Registering a notify handler against the device's node is not enough?
> AFAIR, the spec requires devices that triggered wake-up to be notified and
> most DSDTs I've seen do it in one way or another (usually through _WAK).
Sure, there are a lot of requirements on the ACPI end. We also need to call
_DSW or _PSW (if it's available) when preparing a PCI device for wakeup.
>
> > a function like ->wake() will be called for the device driver that owns
> > the triggered device. This should allow for even runtime PME usage. I'm
> > expecting to have a patch available for the PCI end of these changes soon.
>
> What point is calling this when we're already up?
I think you're defining a scope that is too narrow for wake events.
Remember that they can be enabled during S0 (and there are many good
reasons to do so). In this case, a device is not going to turn on by
itself as ->resume will never be called. Rather, the driver will need
to evaluate the wake event and determine the proper course of action.
>
> Obviously, I haven't seen the whole picture, but from what I know we
> already have a .enable_wake callback that is ignored by both the core code
> and the drivers. Perhaps extending this callback with platform hooks to
> enable the corresponding GPE (die, /proc/acpi/wakeup, die!) and making sure
> it actually is called would suffice?
Yes, I'd like to use platform hooks. The API on the PCI end might look
like this: (in psuedo-code)
pci_arm_wakeup(struct pci_dev *dev,
struct power_state *lowest_state_we_might_enter,
struct system_state *target_system_suspend_state)
{
pci_enable_pme();
enable_platform_wakeup();
}
pci_disarm_wakeup(struct pci_dev *dev)
{
disable_platform_wakeup();
pci_disable_pme();
}
pci_enable_wake() would be deprecated.
Regards,
Adam
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