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PM: Introduce PM_EVENT_HIBERNATE callback state

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During the last step of hibernation in the "platform" mode (with the
help of ACPI) we use the suspend code, including the devices'
->suspend() methods, to prepare the system for entering the ACPI S4
system sleep state.

But at least for some devices the operations performed by the
->suspend() callback in that case must be different from its operations
during regular suspend.

For this reason, introduce the new PM event type PM_EVENT_HIBERNATE and
pass it to the device drivers' ->suspend() methods during the last phase
of hibernation, so that they can distinguish this case and handle it as
appropriate.  Modify the drivers that handle PM_EVENT_SUSPEND in a
special way and need to handle PM_EVENT_HIBERNATE in the same way.

These changes are necessary to fix a hibernation regression related
to the i915 driver (ref. http://lkml.org/lkml/2008/2/22/488).

Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Tested-by: Jeff Chua <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Rafael J. Wysocki 2008-02-23 19:13:25 +01:00 • committed by Linus Torvalds
commit 3a2d5b7001
18 changed files with 42 additions and 24 deletions
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13
Documentation/power/devices.txt
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@ -310,9 +310,12 @@ used with suspend-to-disk:
PM_EVENT_SUSPEND -- quiesce the driver and put hardware into a low-power
state. When used with system sleep states like "suspend-to-RAM" or
"standby", the upcoming resume() call will often be able to rely on
state kept in hardware, or issue system wakeup events. When used
instead with suspend-to-disk, few devices support this capability;
most are completely powered off.
state kept in hardware, or issue system wakeup events.
PM_EVENT_HIBERNATE -- Put hardware into a low-power state and enable wakeup
events as appropriate. It is only used with hibernation
(suspend-to-disk) and few devices are able to wake up the system from
this state; most are completely powered off.
PM_EVENT_FREEZE -- quiesce the driver, but don't necessarily change into
any low power mode. A system snapshot is about to be taken, often
@ -329,8 +332,8 @@ used with suspend-to-disk:
wakeup events nor DMA are allowed.
To enter "standby" (ACPI S1) or "Suspend to RAM" (STR, ACPI S3) states, or
the similarly named APM states, only PM_EVENT_SUSPEND is used; for "Suspend
to Disk" (STD, hibernate, ACPI S4), all of those event codes are used.
the similarly named APM states, only PM_EVENT_SUSPEND is used; the other event
codes are used for hibernation ("Suspend to Disk", STD, ACPI S4).
There's also PM_EVENT_ON, a value which never appears as a suspend event
but is sometimes used to record the "not suspended" device state.