On Wednesday, 2 of January 2008, Nigel Cunningham wrote: > Hi. > > Rafael J. Wysocki wrote: > > On Wednesday, 2 of January 2008, Shaohua Li wrote: > >> ACPI defines a hardware signature. BIOS calculates the signature > >> according to hardware configure, if hardware changes, the signature will > >> change, in this case, S4 resume should fail. > > > > The idea is fine, but I'd prefer to do that in a more straightforward way. > > Namely, we can just: > > * write the signature into a variable in, for example, > > acpi_hibernation_prepare() (then, the "old" signature value will be > > automatically saved in the image) > > * compare it with a the "new" value read from the BIOS in > > acpi_hibernation_leave() and panic if there's a mismatch > > * add a configuration option to disable this behavior (just in case) > > This way we can avoid modifying the entire generic interface to add the feature > > specific to ACPI. > > > > Still, if you want the boot kernel to check the signature, which will be more > > elegant (but please note that on x86-64 the boot kernel need not support ACPI > > at all), you can use the (recently introduced) architecture part of the image > > header for this purpose, without modifying the generic interface. > > I suppose we can always disable this when we start to support hardware > changing over hibernate (I have ideas in this direction - memory cold > plugging, for a start). Well, if we support such features, we won't be following ACPI any more. Greetings, Rafael - 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
