On Fri, 19 Dec 2008, Bjorn Helgaas wrote: > On Friday 19 December 2008 02:23:49 am Len Brown wrote: > > ACPI 2.0 defined two new methods in the suspend/resume sequence, > > _GTS (Going to Sleep) and _BFS (Back from Sleep) > > > > They are optional methods, but if the BIOS supplies them, > > the OS is supposed to evaluate them immediately before > > writing the register to sleep, and immediately after waking up -- > > a time when interrupts are disabled. > > > > ... > > Now, several years after ACPI 2.0 was released, > > we have yet to observe a single implementation of > > _GTS/_BFS in the field -- suggesting that they will > > never actually be deployed. > > There are actually some HP ia64 systems that have _GTS. All > the rx7600-, rx8600-, and Superdome-class systems I looked at > have it. But in each case, the method is empty, so I don't > know why they even bothered to implement it. I've seen "place holders" in AML many times. _SCP is another popular one that is almost never implemented, but sometimes exists and does nothing -- which is quite misleading... > > So lets keep Linux simple by removing this > > theoretical support for _GTS/_BFS, the only > > AML methods that mandated being evaluated > > with interrupts disabled. > > Do you want to print a note that _GTS/_BFS exists, but > we're ignoring it? If some platform comes along that > uses them, a dmesg note might help debug problems. Good idea. Probably the smart thing to do would be to print a message if they exist and are non-empty. Otherwise we'd have to DMI those HP boxes with empty methods. -- Len Brown, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
