On Tuesday, 17 July 2007 22:37, david@xxxxxxx wrote: > On Tue, 17 Jul 2007, Jeremy Maitin-Shepard wrote: > > > "Rafael J. Wysocki" <rjw@xxxxxxx> writes: > > > > [snip] > > > >>> Rafael, for those of us who aren't thoroughly familiar with all the ins > >>> and outs of the ACPI spec, could you please summarize a list of the > >>> ACPI calls needed in the second and third cases above? Indicate which > >>> ones need to be done from within the original kernel and which should > >>> be done from within a kexec'd hibernation kernel. > > > >> Sure. > > > >> In the third case (ie. transition to S4) we are supposed to do the following: > > > >> (1) Upon entering the sleep state, which IMO can be done _after_ the image > >> has been saved: > > > > I assume you mean "in order to enter the sleep state", rather than "upon > > entering the sleep state". I still don't understand what you mean by > > "which IMO can be done _after_ the image has been saved"; as far as I > > understand, the last step of this process, "make the platform enter S4", > > is almost like a shutdown as far as the kernel is concerned (except for > > the tiny detail of having to call those special ACPI methods on resume); > > consequently, it would seem that nothing can be done after that step. > > > >> * figure out which devices can wake up > >> * put devices into low power states (wake-up devices are placed in the Dx > >> states compatible with the wake capability, the others are powered off) > > this can't be done by the image-saving kernel if that kernel doesn't know > about the device. Good observation. :-) Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
