kernel/linux.git/drivers/base/power/main.c, branch v3.2.50

PM / Sleep: Prevent waiting forever on asynchronous suspend after abort

2012-07-04T04:44:27+00:00

commit 1f758b23177d588a71b96ad02990e715949bb82f upstream. __device_suspend() must always send a completion. Otherwise, parent devices will wait forever. Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and system sleep (v2)", introduced a regression by short-circuiting the complete_all() for certain error cases. This patch fixes the bug by always signalling a completion. Addresses http://crosbug.com/31972 Tested by injecting an abort. Signed-off-by: Mandeep Singh Baines Signed-off-by: Rafael J. Wysocki Signed-off-by: Ben Hutchings

PM Sleep: Do not extend wakeup paths to devices with ignore_children set

2011-11-17T20:39:33+00:00

Commit 4ca46ff3e0d8c234cb40ebb6457653b59584426c (PM / Sleep: Mark devices involved in wakeup signaling during suspend) introduced the power.wakeup_path field in struct dev_pm_info to mark devices whose children are enabled to wake up the system from sleep states, so that power domains containing the parents that provide their children with wakeup power and/or relay their wakeup signals are not turned off. Unfortunately, that introduced a PM regression on SH7372 whose power consumption in the system "memory sleep" state increased as a result of it, because it prevented the power domain containing the I2C controller from being turned off when some children of that controller were enabled to wake up the system, although the controller was not necessary for them to signal wakeup. To fix this issue use the observation that devices whose power.ignore_children flag is set for runtime PM should be treated analogously during system suspend. Namely, they shouldn't be included in wakeup paths going through their children. Since the SH7372 I2C controller's power.ignore_children flag is set, doing so will restore the previous behavior of that SOC. Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman

drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required.

2011-10-31T23:31:38+00:00

Most of these files were implicitly getting EXPORT_SYMBOL via device.h which was including module.h, but that path will be broken soon. [ with input from Stephen Rothwell ] Signed-off-by: Paul Gortmaker

Merge branch 'pm-domains' into pm-for-linus

2011-10-21T22:21:52+00:00

* pm-domains: ARM: mach-shmobile: sh7372 A4R support (v4) ARM: mach-shmobile: sh7372 A3SP support (v4) PM / Sleep: Mark devices involved in wakeup signaling during suspend

PM / Sleep: Mark devices involved in wakeup signaling during suspend

2011-10-21T22:19:29+00:00

The generic PM domains code in drivers/base/power/domain.c has to avoid powering off domains that provide power to wakeup devices during system suspend. Currently, however, this only works for wakeup devices directly belonging to the given domain and not for their children (or the children of their children and so on). Thus, if there's a wakeup device whose parent belongs to a power domain handled by the generic PM domains code, the domain will be powered off during system suspend preventing the device from signaling wakeup. To address this problem introduce a device flag, power.wakeup_path, that will be set during system suspend for all wakeup devices, their parents, the parents of their parents and so on. This way, all wakeup paths in the device hierarchy will be marked and the generic PM domains code will only need to avoid powering off domains containing devices whose power.wakeup_path is set. Signed-off-by: Rafael J. Wysocki

PM / Suspend: Add statistics debugfs file for suspend to RAM

2011-10-16T21:27:45+00:00

Record S3 failure time about each reason and the latest two failed devices' names in S3 progress. We can check it through 'suspend_stats' entry in debugfs. The motivation of the patch: We are enabling power features on Medfield. Comparing with PC/notebook, a mobile enters/exits suspend-2-ram (we call it s3 on Medfield) far more frequently. If it can't enter suspend-2-ram in time, the power might be used up soon. We often find sometimes, a device suspend fails. Then, system retries s3 over and over again. As display is off, testers and developers don't know what happens. Some testers and developers complain they don't know if system tries suspend-2-ram, and what device fails to suspend. They need such info for a quick check. The patch adds suspend_stats under debugfs for users to check suspend to RAM statistics quickly. If not using this patch, we have other methods to get info about what device fails. One is to turn on CONFIG_PM_DEBUG, but users would get too much info and testers need recompile the system. In addition, dynamic debug is another good tool to dump debug info. But it still doesn't match our utilization scenario closely. 1) user need write a user space parser to process the syslog output; 2) Our testing scenario is we leave the mobile for at least hours. Then, check its status. No serial console available during the testing. One is because console would be suspended, and the other is serial console connecting with spi or HSU devices would consume power. These devices are powered off at suspend-2-ram. Signed-off-by: ShuoX Liu Signed-off-by: Rafael J. Wysocki

PM / QoS: Add function dev_pm_qos_read_value() (v3)

2011-10-04T19:54:26+00:00

To read the current PM QoS value for a given device we need to make sure that the device's power.constraints object won't be removed while we're doing that. For this reason, put the operation under dev->power.lock and acquire the lock around the initialization and removal of power.constraints. Moreover, since we're using the value of power.constraints to determine whether or not the object is present, the power.constraints_state field isn't necessary any more and may be removed. However, dev_pm_qos_add_request() needs to check if the device is being removed from the system before allocating a new PM QoS constraints object for it, so make it use the power.power_state field of struct device for this purpose. Signed-off-by: Rafael J. Wysocki

PM QoS: Implement per-device PM QoS constraints

2011-08-25T13:35:41+00:00

Implement the per-device PM QoS constraints by creating a device PM QoS API, which calls the PM QoS constraints management core code. The per-device latency constraints data strctures are stored in the device dev_pm_info struct. The device PM code calls the init and destroy of the per-device constraints data struct in order to support the dynamic insertion and removal of the devices in the system. To minimize the data usage by the per-device constraints, the data struct is only allocated at the first call to dev_pm_qos_add_request. The data is later free'd when the device is removed from the system. A global mutex protects the constraints users from the data being allocated and free'd. Signed-off-by: Jean Pihet Reviewed-by: Kevin Hilman Signed-off-by: Rafael J. Wysocki

PM: Limit race conditions between runtime PM and system sleep (v2)

2011-07-06T08:51:58+00:00

One of the roles of the PM core is to prevent different PM callbacks executed for the same device object from racing with each other. Unfortunately, after commit e8665002477f0278f84f898145b1f141ba26ee26 (PM: Allow pm_runtime_suspend() to succeed during system suspend) runtime PM callbacks may be executed concurrently with system suspend/resume callbacks for the same device. The main reason for commit e8665002477f0278f84f898145b1f141ba26ee26 was that some subsystems and device drivers wanted to use runtime PM helpers, pm_runtime_suspend() and pm_runtime_put_sync() in particular, for carrying out the suspend of devices in their .suspend() callbacks. However, as it's been determined recently, there are multiple reasons not to do so, inlcuding: * The caller really doesn't control the runtime PM usage counters, because user space can access them through sysfs and effectively block runtime PM. That means using pm_runtime_suspend() or pm_runtime_get_sync() to suspend devices during system suspend may or may not work. * If a driver calls pm_runtime_suspend() from its .suspend() callback, it causes the subsystem's .runtime_suspend() callback to be executed, which leads to the call sequence: subsys->suspend(dev) driver->suspend(dev) pm_runtime_suspend(dev) subsys->runtime_suspend(dev) recursive from the subsystem's point of view. For some subsystems that may actually work (e.g. the platform bus type), but for some it will fail in a rather spectacular fashion (e.g. PCI). In each case it means a layering violation. * Both the subsystem and the driver can provide .suspend_noirq() callbacks for system suspend that can do whatever the .runtime_suspend() callbacks do just fine, so it really isn't necessary to call pm_runtime_suspend() during system suspend. * The runtime PM's handling of wakeup devices is usually different from the system suspend's one, so .runtime_suspend() may simply be inappropriate for system suspend. * System suspend is supposed to work even if CONFIG_PM_RUNTIME is unset. * The runtime PM workqueue is frozen before system suspend, so if whatever the driver is going to do during system suspend depends on it, that simply won't work. Still, there is a good reason to allow pm_runtime_resume() to succeed during system suspend and resume (for instance, some subsystems and device drivers may legitimately use it to ensure that their devices are in full-power states before suspending them). Moreover, there is no reason to prevent runtime PM callbacks from being executed in parallel with the system suspend/resume .prepare() and .complete() callbacks and the code removed by commit e8665002477f0278f84f898145b1f141ba26ee26 went too far in this respect. On the other hand, runtime PM callbacks, including .runtime_resume(), must not be executed during system suspend's "late" stage of suspending devices and during system resume's "early" device resume stage. Taking all of the above into consideration, make the PM core acquire a runtime PM reference to every device and resume it if there's a runtime PM resume request pending right before executing the subsystem-level .suspend() callback for it. Make the PM core drop references to all devices right after executing the subsystem-level .resume() callbacks for them. Additionally, make the PM core disable the runtime PM framework for all devices during system suspend, after executing the subsystem-level .suspend() callbacks for them, and enable the runtime PM framework for all devices during system resume, right before executing the subsystem-level .resume() callbacks for them. Signed-off-by: Rafael J. Wysocki Acked-by: Kevin Hilman

PM / Domains: Rename struct dev_power_domain to struct dev_pm_domain

2011-07-02T12:29:54+00:00

The naming convention used by commit 7538e3db6e015e890825fbd9f86599b (PM: Add support for device power domains), which introduced the struct dev_power_domain type for representing device power domains, evidently confuses some developers who tend to think that objects of this type must correspond to "power domains" as defined by hardware, which is not the case. Namely, at the kernel level, a struct dev_power_domain object can represent arbitrary set of devices that are mutually dependent power management-wise and need not belong to one hardware power domain. To avoid that confusion, rename struct dev_power_domain to struct dev_pm_domain and rename the related pointers in struct device and struct pm_clk_notifier_block from pwr_domain to pm_domain. Signed-off-by: Rafael J. Wysocki Acked-by: Kevin Hilman