On Thursday, 15 of May 2008, Eric W. Biederman wrote: > "Rafael J. Wysocki" <rjw@xxxxxxx> writes: > > > On Saturday, 22 of March 2008, Alan Stern wrote: > > > The spec doesn't say much about that, so we'll need to carry out some > > experiments. > > > Still, as far as I can figure out what the spec authors _might_ mean, I think > > that it would be inappropriate to restore the ACPI NVS area if S5 was entered > > on "power off". The idea seems to be that the restoration of the ACPI NVS area > > should complement whatever has been preserved by the platform over the > > hibernation/resume cycle. > > > IMO, if S5 was entered on "powe off", there are two possible ways to go. > > Either ACPI is initialized by the boot kernel, in which case the image kernel > > should not touch things like _WAK and similar, just throw away whatever > > ACPI-related state it got from the image and try to rebuild the ACPI-related > > data from scratch. Or the boot kernel doesn't touch ACPI and the image kernel > > initializes it in the same way as during a fresh boot (that might be difficult, > > though). > > Just an added data partial point. In the kexec case I have had not heard > anyone screaming to me that ACPI doesn't work after we switch kernels. You don't remove power from devices while doing that. > So I expect shutting down ACPI and restarting it should work reliably > and that is easy to test as that is already implemented with kexec. You can't program devices to generate wakeup events without ACPI, among other things. Anyway, I don't think you should focus on replacing the current hibernation code entirely so much. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
