Messages in this thread | | | Date | Tue, 3 Feb 2009 09:53:08 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: PCI PM: Restore standard config registers of all devices early |
| |
On Tue, 3 Feb 2009, Rafael J. Wysocki wrote: > > As I said, I tend to prefer the "loop of disable_irq()" approach, because it > would allow us to preserve the current ordering of ACPI operations. Namely, > if we do: > > suspend devices (normal suspend) > loop of disable_irq() > late suspend of devices > _PTS > disable nonboot CPUs > local_irq_disable() > sysdev suspend > enter sleep state > get control from the BIOS > sysdev resume > (*) > local_irq_enable() > enable nonboot CPUs > _WAK > early resume of devices > loop of enable_irq() > resume devices (normal resume) > > the ordering of _PTS with respect to putting devices into low power states and > disabling the nonboot CPUs will be the same as it is now and the same applies > to _WAK and putting devices into D0 etc. (I really _really_ wouldn't like to > change this ordering, since this alone is likely to break things badly).
Yes.
Also, make the "loop of disable/enable_irq()" phase be a helper function that also sets system_state to SYSTEM_SUSPENDING/SYSTEM_RUNNING respectively, and it should all be pretty clean, and the changes really should be pretty minimal.
> Now, there's one subtle problem with resume in this picture. Namely, before > running the "early resume of devices" we have to make sure that the interrupts > will be masked. However, masking MSI-X, for example, means writing into > the memory space of the device, so we can't do it at this point.
I really don't think it matters. Why? We simply don't care.
All MSI-X things will still have to go through the regular irq layer, so the disable/enable_irq part, so even though we've done the "local_irq_enable()", we just don't care.
Linus
| |