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power management: force pm_ops.valid callback to be assigned

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This patch changes the docs and behaviour from "all states valid" to "no
states valid" if no .valid callback is assigned.  Users of pm_ops that only
need mem sleep can assign pm_valid_only_mem without any overhead, others
will require more elaborate callbacks.

Now that all users of pm_ops have a .valid callback this is a safe thing to
do and prevents things from getting messy again as they were before.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Looks-okay-to: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <linux-pm@lists.linux-foundation.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Berg 2007-04-30 15:09:55 -07:00 committed by Linus Torvalds
parent e8c9c50269
commit 9684e51cd1
2 changed files with 8 additions and 8 deletions
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12
include/linux/pm.h
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@ -125,12 +125,12 @@ typedef int __bitwise suspend_disk_method_t;
* struct pm_ops - Callbacks for managing platform dependent suspend states.
* @valid: Callback to determine whether the given state can be entered.
* If %CONFIG_SOFTWARE_SUSPEND is set then %PM_SUSPEND_DISK is
* always valid and never passed to this call.
* If not assigned, all suspend states are advertised as valid
* in /sys/power/state (but can still be rejected by prepare or enter.)
* Since new states can be added for other platforms, you should
* assign this callback. There is a %pm_valid_only_mem function
* available if you only implemented mem sleep.
* always valid and never passed to this call. If not assigned,
* no suspend states are valid.
* Valid states are advertised in /sys/power/state but can still
* be rejected by prepare or enter if the conditions aren't right.
* There is a %pm_valid_only_mem function available that can be assigned
* to this if you only implement mem sleep.
*
* @prepare: Prepare the platform for the given suspend state. Can return a
* negative error code if necessary.

4
kernel/power/main.c
View File

@ -198,8 +198,8 @@ static inline int valid_state(suspend_state_t state)
/* all other states need lowlevel support and need to be
* valid to the lowlevel implementation, no valid callback
* implies that all are valid. */
if (!pm_ops || (pm_ops->valid && !pm_ops->valid(state)))
* implies that none are valid. */
if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
return 0;
return 1;
}