Re: x86: Increase PCIBIOS_MIN_IO to 0x1500 to fix nForce 4 suspend-to-RAM

[Carlos Corbacho <carlos@strangeworlds.co.uk>]

On Monday 24 December 2007 18:34:21 Linus Torvalds wrote:
> On Mon, 24 Dec 2007, Rafael J. Wysocki wrote:
> > Well, having considered that for a longer while, I think the AML code is
> > referring to a device that we have suspended already, and since it's in a
> > low power state, it just can't handle the reference.
> >
> > If that is the case, we'll have to find the device (that should be
> > possible using some code instrumentation) and move the suspending of it
> > into the late stage.
>
> Yes.

My own experimentation (in device_suspend(), calling _PTS() in the AML after 
each suspend_device() runs, until one device causes it to hang) points to 
ohci_hcd being the culprit here (with or without any devices attached). With 
the ohci_hcd module unloaded, the machine suspends just fine[1].

Of course, I'm at a complete loss as to why suspending OHCI would cause a 
problem for an IO port write.

> NOTE! This following patch is just for discussion, and while I think it's
> conceptually a good thing to try, I don't think it will help Carlos'
> problem. But removing the "pci_set_power_state()" in agp_nvidia_suspend()
> might.

nvidia-agp cannot be built on x86-64, so it's not the culprit in this case.

-Carlos

[1] And yes, I double checked the custom DSDT is not loaded this time.
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