This patch changes /sys/power/state to not advertise any valid states (except for disk if SOFTWARE_SUSPEND is enabled) when no pm_ops have been set so userspace can easily discover what states should be available. Also, because the pm ops in powermac are obviously not using them as intended, I added documentation for it in kernel-doc format. Reordering the fields in struct pm_ops not only makes the output of kernel-doc make more sense but also removes a hole from the structure on 64-bit platforms. Signed-off-by: Johannes Berg <johannes at sipsolutions.net> Acked-by: Pavel Macheck <pavel at ucw.cz> Cc: Rafael J. Wysocki <rjw at sisk.pl> Cc: linux-pm at lists.osdl.org --- include/linux/pm.h | 36 ++++++++++++++++++++++++++++++++++-- kernel/power/main.c | 5 ++++- 2 files changed, 38 insertions(+), 3 deletions(-) --- linux-2.6-git.orig/kernel/power/main.c 2007-02-08 19:23:44.179643144 +0100 +++ linux-2.6-git/kernel/power/main.c 2007-02-08 19:23:54.201643144 +0100 @@ -161,7 +161,10 @@ static inline int valid_state(suspend_st if (state == PM_SUSPEND_DISK) return 1; - if (pm_ops && pm_ops->valid && !pm_ops->valid(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))) return 0; return 1; } --- linux-2.6-git.orig/include/linux/pm.h 2007-02-08 19:23:44.219643144 +0100 +++ linux-2.6-git/include/linux/pm.h 2007-02-08 19:23:54.204643144 +0100 @@ -120,15 +120,47 @@ typedef int __bitwise suspend_disk_metho #define PM_DISK_TESTPROC ((__force suspend_disk_method_t) 6) #define PM_DISK_MAX ((__force suspend_disk_method_t) 7) +/** + * 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.) + * @prepare: Prepare the platform for the given suspend state. Can return a + * negative error code if necessary. + * @enter: Enter the given suspend state, must be assigned. Can return a + * negative error code if necessary. + * @finish: Called when the system has left the given state and all devices + * are resumed. The return value is ignored. + * @pm_disk_mode: Set to the disk method that the user should be able to + * configure for suspend-to-disk. Since %PM_DISK_SHUTDOWN, + * %PM_DISK_REBOOT, %PM_DISK_TEST and %PM_DISK_TESTPROC + * are always allowed, currently only %PM_DISK_PLATFORM + * makes sense. If the user then choses %PM_DISK_PLATFORM, + * the @prepare call will be called before suspending to disk + * (if present), the @enter call should be present and will + * be called after all state has been saved and the machine + * is ready to be shut down/suspended/..., and the @finish + * callback is called after state has been restored. All + * these calls are called with %PM_SUSPEND_DISK as the state. + */ struct pm_ops { - suspend_disk_method_t pm_disk_mode; int (*valid)(suspend_state_t state); int (*prepare)(suspend_state_t state); int (*enter)(suspend_state_t state); int (*finish)(suspend_state_t state); + suspend_disk_method_t pm_disk_mode; }; -extern void pm_set_ops(struct pm_ops *); +/** + * pm_set_ops - set platform dependent power management ops + * @pm_ops: The new power management operations to set. + */ +extern void pm_set_ops(struct pm_ops *pm_ops); extern struct pm_ops *pm_ops; extern int pm_suspend(suspend_state_t state);