From: Rafael J. Wysocki <[email protected]> Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to resume all runtime-suspended devices during system suspend, mostly because those devices may need to be reprogrammed due to different wakeup settings for system sleep and runtime PM. However, at least in some cases that isn't really necessary, because the wakeup settings aren't really different.
The idea here is that subsystems should know whether or not it is necessary to reprogram a given device during system suspend and they should be able to tell the PM core about that. For this reason, modify the PM core so that if the .prepare() callback returns a positive value for certain device, the core will set a new power.no_suspend flag for it. Then, if that flag is set, the core will skip all of the subsequent suspend callbacks for that device. However, since parents may need to be resumed so that their children can be reprogrammed, make the PM core clear power.no_suspend for devices that don't have power.ignore_children set and whose children don't have power.no_suspend set. Signed-off-by: Rafael J. Wysocki <[email protected]> --- drivers/base/power/main.c | 38 ++++++++++++++++++++++++++------------ include/linux/pm.h | 1 + 2 files changed, 27 insertions(+), 12 deletions(-) Index: linux-pm/drivers/base/power/main.c =================================================================== --- linux-pm.orig/drivers/base/power/main.c +++ linux-pm/drivers/base/power/main.c @@ -918,7 +918,7 @@ static int device_suspend_noirq(struct d pm_callback_t callback = NULL; char *info = NULL; - if (dev->power.syscore) + if (dev->power.syscore || dev->power.no_suspend) return 0; if (dev->pm_domain) { @@ -1006,7 +1006,7 @@ static int device_suspend_late(struct de __pm_runtime_disable(dev, false); - if (dev->power.syscore) + if (dev->power.syscore || dev->power.no_suspend) return 0; if (dev->pm_domain) { @@ -1143,8 +1143,10 @@ static int __device_suspend(struct devic * for it, this is equivalent to the device signaling wakeup, so the * system suspend operation should be aborted. */ - if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) + if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) { pm_wakeup_event(dev, 0); + dev->power.no_suspend = false; + } if (pm_wakeup_pending()) { async_error = -EBUSY; @@ -1157,6 +1159,9 @@ static int __device_suspend(struct devic dpm_watchdog_set(&wd, dev); device_lock(dev); + if (dev->power.no_suspend) + goto End; + if (dev->pm_domain) { info = "power domain "; callback = pm_op(&dev->pm_domain->ops, state); @@ -1205,9 +1210,13 @@ static int __device_suspend(struct devic End: if (!error) { dev->power.is_suspended = true; - if (dev->power.wakeup_path - && dev->parent && !dev->parent->power.ignore_children) - dev->parent->power.wakeup_path = true; + if (dev->parent && !dev->parent->power.ignore_children) { + if (dev->power.wakeup_path) + dev->parent->power.wakeup_path = true; + + if (!dev->power.no_suspend) + dev->parent->power.no_suspend = false; + } } device_unlock(dev); @@ -1307,7 +1316,7 @@ static int device_prepare(struct device { int (*callback)(struct device *) = NULL; char *info = NULL; - int error = 0; + int ret = 0; if (dev->power.syscore) return 0; @@ -1323,6 +1332,7 @@ static int device_prepare(struct device device_lock(dev); dev->power.wakeup_path = device_may_wakeup(dev); + dev->power.no_suspend = false; if (dev->pm_domain) { info = "preparing power domain "; @@ -1344,16 +1354,20 @@ static int device_prepare(struct device } if (callback) { - error = callback(dev); - suspend_report_result(callback, error); + ret = callback(dev); + suspend_report_result(callback, ret); } device_unlock(dev); - if (error) + if (ret < 0) { pm_runtime_put(dev); + } else if (ret > 0) { + dev->power.no_suspend = true; + ret = 0; + } - return error; + return ret; } /** @@ -1422,7 +1436,7 @@ EXPORT_SYMBOL_GPL(dpm_suspend_start); void __suspend_report_result(const char *function, void *fn, int ret) { - if (ret) + if (ret < 0) printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret); } EXPORT_SYMBOL_GPL(__suspend_report_result); Index: linux-pm/include/linux/pm.h =================================================================== --- linux-pm.orig/include/linux/pm.h +++ linux-pm/include/linux/pm.h @@ -544,6 +544,7 @@ struct dev_pm_info { bool is_suspended:1; /* Ditto */ bool ignore_children:1; bool early_init:1; /* Owned by the PM core */ + bool no_suspend:1; spinlock_t lock; #ifdef CONFIG_PM_SLEEP struct list_head entry; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
