Messages in this thread Patch in this message | | | Date | Mon, 10 May 2004 18:00:15 -0700 | From | Todd Poynor <> | Subject | Hotplug events for system suspend/resume |
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Generate synchronous hotplug events for system suspend and resume events, via the power subsystem. Recent discussions have indicated various methods for notification of these events are in use today; this is an attempt to move these into the generic power subsystem. The patch relies on the "synchronous hotplug events via kobject" patch sent previously.
I fumbled around with the best to way to hook this into kobject. Subsystems apparently aren't setup to generate hotplug events directly, only kobjects below a subsystem may issue hotplug events. A notifier kobject has been created within the power subsystem for this purpose. Any advice welcome.
Thanks -- Todd
--- linux-2.6.6-orig/kernel/power/main.c 2004-05-10 11:26:35.000000000 -0700 +++ linux-2.6.6-pm/kernel/power/main.c 2004-05-10 17:25:30.000000000 -0700 @@ -25,6 +25,9 @@ struct pm_ops * pm_ops = NULL; u32 pm_disk_mode = PM_DISK_SHUTDOWN; +int pm_state = PM_SUSPEND_ON; + +static void power_notify(void); /** * pm_set_ops - Set the global power method table. @@ -150,20 +153,26 @@ goto Unlock; } + pm_state = state; + power_notify(); + if (state == PM_SUSPEND_DISK) { error = pm_suspend_disk(); - goto Unlock; + goto NotifyUnlock; } pr_debug("PM: Preparing system for suspend\n"); if ((error = suspend_prepare(state))) - goto Unlock; + goto NotifyUnlock; pr_debug("PM: Entering state.\n"); error = suspend_enter(state); pr_debug("PM: Finishing up.\n"); suspend_finish(state); + NotifyUnlock: + pm_state = PM_SUSPEND_ON; + power_notify(); Unlock: up(&pm_sem); return error; @@ -186,8 +195,28 @@ } +static int power_hotplug(struct kset *kset, struct kobject *kobj, char **envp, + int num_envp, char *buffer, int buffer_size) +{ + int i = 0; + int length = 0; -decl_subsys(power,NULL,NULL); + envp[i++] = buffer; + length += scnprintf (buffer, buffer_size - length, "STATE=%s", + pm_states[pm_state] ? pm_states[pm_state] : "on"); + if ((buffer_size - length <= 0) || (i >= num_envp)) + return -ENOMEM; + ++length; + + envp[i] = 0; + return 0; +} + +static struct kset_hotplug_ops power_hotplug_ops = { + .hotplug = power_hotplug, +}; + +decl_subsys(power,NULL,&power_hotplug_ops); /** @@ -247,12 +276,28 @@ .attrs = g, }; +struct power_notifier { + struct kobject kobj; +}; + +static struct power_notifier power_notifier; + +static void power_notify() +{ + kobject_hotplug_wait("state-change", &power_notifier.kobj); +} static int __init pm_init(void) { int error = subsystem_register(&power_subsys); if (!error) error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group); + if (!error) { + kobj_set_kset_s(&power_notifier, power_subsys); + error = kobject_set_name(&power_notifier.kobj, "notifier"); + if (! error) + kobject_register(&power_notifier.kobj); + } return error; }
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