On Thursday, 3 of January 2008, Shaohua Li wrote: > > On Wed, 2008-01-02 at 22:05 +0800, 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. > it would be better we do the check in boot kernel. Franky, I think we should also check in the image kernel, in case the boot one doesn't support ACPI as I said. > Why is so bad to do it in generic code? I just don't like adding more callbacks for this purpose. > Other platforms can implement it too, like calculating the signature in OS. > > > 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. > Where can I get the code with architecture image header support? appears > can't find it. Please have a look at arch_hibernation_header_save() and arch_hibernation_header_restore() in arch/x86/kernel/suspend_64.c. They are used by init_header_complete() and check_image_kernel() defined in kernel/power/power.h . Currently only x86_64 defines these functions, but I'm going to implement them on i386 too. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
