to resume the system from RAM if there's enough battery power or restore
its state on the basis of the saved suspend image otherwise)
-SNAPSHOT_PMOPS - enable the usage of the pmops->prepare, pmops->enter and
- pmops->finish methods (the in-kernel swsusp knows these as the "platform
- method") which are needed on many machines to (among others) speed up
- the resume by letting the BIOS skip some steps or to let the system
- recognise the correct state of the hardware after the resume (in
- particular on many machines this ensures that unplugged AC
- adapters get correctly detected and that kacpid does not run wild after
- the resume). The last ioctl() argument can take one of the three
- values, defined in kernel/power/power.h:
+SNAPSHOT_PMOPS - enable the usage of the hibernation_ops->prepare,
+ hibernate_ops->enter and hibernation_ops->finish methods (the in-kernel
+ swsusp knows these as the "platform method") which are needed on many
+ machines to (among others) speed up the resume by letting the BIOS skip
+ some steps or to let the system recognise the correct state of the
+ hardware after the resume (in particular on many machines this ensures
+ that unplugged AC adapters get correctly detected and that kacpid does
+ not run wild after the resume). The last ioctl() argument can take one
+ of the three values, defined in kernel/power/power.h:
PMOPS_PREPARE - make the kernel carry out the
- pm_ops->prepare(PM_SUSPEND_DISK) operation
+ hibernation_ops->prepare() operation
PMOPS_ENTER - make the kernel power off the system by calling
- pm_ops->enter(PM_SUSPEND_DISK)
+ hibernation_ops->enter()
PMOPS_FINISH - make the kernel carry out the
- pm_ops->finish(PM_SUSPEND_DISK) operation
+ hibernation_ops->finish() operation
+ Note that the actual constants are misnamed because they surface
+ internal kernel implementation details that have changed.
The device's read() operation can be used to transfer the snapshot image from
the kernel. It has the following limitations: