On 9/21/07, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Friday, 21 September 2007 15:14, huang ying wrote: > > On 9/21/07, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > > > On Friday, 21 September 2007 05:33, Eric W. Biederman wrote: > > > > Nigel Cunningham <nigel@xxxxxxxxxxxxxxxxxx> writes: > [--snip--] > > > > > > > > No one has yet attacked the hard problem of coming up with separate > > > > hibernate methods for drivers. > > > > > > Well, I've been playing a bit with that for some time, but it's not easy by any > > > means. > > > > > > In short, I'm seeing some problems related to the handling of ACPI that seem to > > > shatter the entire idea of having separate hibernate methods, at least as far > > > as ACPI systems are concerned. > > > > So sadly to hear this. Can you details it a little? Or a link? > > Well, the problem is that apparently some systems (eg. my HP nx6325) expect us > to execute the _PTS ACPI global control method before creating the image _and_ > to execute acpi_enter_sleep_state(ACPI_STATE_S4) in order to finally put the > system into the sleep state. In particular, on nx6325, if we don't do that, > then after the restore the status of the AC power will not be reported > correctly (and if you replace the battery while in the sleep state, the > battery status will not be updated correctly after the restore). Similar > issues have been reported for other machines. > > Now, the ACPI specification requires us to put devices into low power states > before executing _PTS and that's exactly what we're doing before a suspend to > RAM. Thus, it seems that in general we need to do the same for hibernation on > ACPI systems. Then, is it possible to separate device quiesce from device suspend. Perhaps not for swsusp, but for kexec based hibernation? Best Regards, Huang Ying _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
