Re: [RFC][PATCH 1/3] PM: Introduce new top level suspend and hibernation callbacks

Pavel Machek
2008-03-18T10:01:06Z

Hi!

> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

ACK.

> + * The externally visible transitions are handled with the help of the following
> + * callbacks included in this structure:
> + *
> + * @prepare: Prepare the device for the upcoming transition, but do NOT change
> + * its hardware state. Prevent new children of the device from being
> + * registered and prevent new calls to the probe method from being made
> + * after @prepare() returns. Also, if a concurrent child registration
> + * or a call to the probe method already in progress is detected by
> + * @prepare(), it may return -EAGAIN, so that the PM core can execute it
> + * once again (e.g. after suspending the newly registered child) to recover
> + * from the race condition. This method is executed for all kinds of
> + * suspend transitions and is immediately followed by one of the suspend
> + * callbacks: @suspend(), @freeze(), @poweroff(), or @quiesce().
> + *
> + * @complete: Undo the changes made by @prepare(). This method is executed for
> + * all kinds of resume transitions, immediately following one of the resume
> + * callbacks: @resume(), @thaw(), @restore(), or @recover(). Also executed
> + * if a suspend callback (@suspend(), @freeze(), @poweroff(), @quiesce())
> + * immediately following a successful @prepare() fails OR if a new child
> + * of the device has been registered during @prepare().

So... we do prepare() but it detects new child, so it returns -EAGAIN.
so we call complete() based on description above
...and then we call prepare() to suspend again?

> + * @suspend: Executed before putting the system into a sleep state in which the
> + * contents of main memory are preserved. Quiesce the device, put it into

content....is?

> + * @resume: Executed after waking the system up from a sleep state in which the
> + * contents of main memory were preserved. Put the device into the

content...is?

> + * @freeze: Hibernation-specific, executed before creating a hibernation image.
> + * Quiesce operations so that a consistent image can be created, but do NOT
> + * otherwise put the device into a low power device state and do NOT emit
> + * system wakeup events. Save in main memory the device settings to be

"Save device settings (used by @restore()) into main memory"?

> + * @quiesce: Hibernation-specific, executed after loading a hibernation image
> + * and before restoring the contents of main memory from it. Quiesce
> + * operations so that the contents of main memory can be restored from the

operations, so ?
Pavel

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