struct bus_type {
...
int (*suspend)(struct device *dev, pm_message_t state);
- int (*suspend_late)(struct device *dev, pm_message_t state);
-
- int (*resume_early)(struct device *dev);
int (*resume)(struct device *dev);
};
This call should handle parts of device suspend logic that require
sleeping. It probably does work to quiesce the device which hasn't
- been abstracted into class.suspend() or bus.suspend_late().
-
- 3 bus.suspend_late(dev, message) is called with IRQs disabled, and
- with only one CPU active. Until the bus.resume_early() phase
- completes (see later), IRQs are not enabled again. This method
- won't be exposed by all busses; for message based busses like USB,
- I2C, or SPI, device interactions normally require IRQs. This bus
- call may be morphed into a driver call with bus-specific parameters.
-
- This call might save low level hardware state that might otherwise
- be lost in the upcoming low power state, and actually put the
- device into a low power state ... so that in some cases the device
- may stay partly usable until this late. This "late" call may also
- help when coping with hardware that behaves badly.
+ been abstracted into class.suspend().
The pm_message_t parameter is currently used to refine those semantics
(described later).
The phases are seen by driver notifications issued in this order:
- 1 bus.resume_early(dev) is called with IRQs disabled, and with
- only one CPU active. As with bus.suspend_late(), this method
- won't be supported on busses that require IRQs in order to
- interact with devices.
-
- This reverses the effects of bus.suspend_late().
-
- 2 bus.resume(dev) is called next. This may be morphed into a device
- driver call with bus-specific parameters; implementations may sleep.
-
- This reverses the effects of bus.suspend().
+ 1 bus.resume(dev) reverses the effects of bus.suspend(). This may
+ be morphed into a device driver call with bus-specific parameters;
+ implementations may sleep.
- 3 class.resume(dev) is called for devices associated with a class
+ 2 class.resume(dev) is called for devices associated with a class
that has such a method. Implementations may sleep.
This reverses the effects of class.suspend(), and would usually
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "EARLY ");
error = pm_noirq_op(dev, dev->bus->pm, state);
- } else if (dev->bus->resume_early) {
- pm_dev_dbg(dev, state, "legacy EARLY ");
- error = dev->bus->resume_early(dev);
}
End:
TRACE_RESUME(error);
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "LATE ");
error = pm_noirq_op(dev, dev->bus->pm, state);
- } else if (dev->bus->suspend_late) {
- pm_dev_dbg(dev, state, "legacy LATE ");
- error = dev->bus->suspend_late(dev, state);
- suspend_report_result(dev->bus->suspend_late, error);
}
return error;
}