Re: [linux-usb-devel] ehci_hcd causes box to resume immediately after suspend to RAM

On Sat, 9 Jun 2007, Rafael J. Wysocki wrote:

> > You can try using the patch below to see what happens when you manually
> > suspend the controller.  It enables PCI devices to respond to the
> > legacy power/state attribute.  You should look at what "lspci -vv" says
> > about the controller's power management signals, both before and after
> > suspending the PCI device entry.
> 
> It works as expected, AFAICS.  That is, after I echo '2' to the 'state' file,
> it shows that the controller is in D3.

At that point, does "lspci -vv" show that the controller is trying to 
signal a wakeup event?  That is, is the PME# signal asserted?

(Not that knowing this will help very much -- I'm not sure what we 
could do with that information, and in any case there are other ways 
besides PME# for on-board devices to report wakeup requests.  I ask 
mainly out of curiousity.)

> I've tried to suspend with the controller in that state, but it's resumed
> immediately, as before.
> 
> > Maybe also see what ACPI reports.
> 
> How can I see that?

I wish I knew.  Maybe you can try asking on the ACPI mailing list.

The simplest workaround should be to disable remote wakeup for that 
controller:

	echo disable >/sys/bus/pci/devices/.../power/wakeup

Alan Stern