kernel/linux.git/drivers/base/power, branch linux-2.6.35.y

PM: Prevent waiting forever on asynchronous resume after failing suspend

2010-09-27T00:18:37+00:00

commit 152e1d592071c8b312bb898bc1118b64e4aea535 upstream. During suspend, the power.completion is expected to be set when a device has not yet started suspending. Set it on init to fix a corner case where a device is resumed when its parent has never suspended. Consider three drivers, A, B, and C. The parent of A is C, and C has async_suspend set. On boot, C->power.completion is initialized to 0. During the first suspend: suspend_devices_and_enter(...) dpm_resume(...) device_suspend(A) device_suspend(B) returns error, aborts suspend dpm_resume_end(...) dpm_resume(...) device_resume(A) dpm_wait(A->parent == C) wait_for_completion(C->power.completion) The wait_for_completion will never complete, because complete_all(C->power.completion) will only be called from device_suspend(C) or device_resume(C), neither of which is called if suspend is aborted before C. After a successful suspend->resume cycle, where B doesn't abort suspend, C->power.completion is left in the completed state by the call to device_resume(C), and the same call path will work if B aborts suspend. Signed-off-by: Colin Cross Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PM / Runtime: Add sysfs debug files

2010-05-10T21:08:17+00:00

Add a few sysfs files relating to runtime power management for advanced debug purposes: runtime_enabled: is runtime PM enabled for this device? States are "enabled", "disabled", "forbidden" or a combination of the latter two. runtime_status: what state is the device in currently? E.g., it reports "suspended" for runtime-suspended devices, and "active" for active devices. NOTE: if runtime_enabled returns "disabled", the value of this file may not reflect its physical state. runtime_usage: the runtime PM usage count of a device runtime_active_kids: the runtime PM children usage count of a device, or 0 if the ignore_children flag is set. Also, CONFIG_PM_SLEEP_ADVANCED_DEBUG is not defined in any Kconfig file, so replace it with CONFIG_PM_ADVANCED_DEBUG. Signed-off-by: Dominik Brodowski Acked-by: Alan Stern Signed-off-by: Rafael J. Wysocki

PM: Allow runtime_suspend methods to call pm_schedule_suspend()

2010-05-10T21:08:16+00:00

This patch (as1361) changes the runtime PM interface slightly; it allows suspend requests to be scheduled while the runtime_suspend method is running. If the method succeeds then the scheduled request is cancelled, whereas if the method fails then an idle notification is sent only if no request was scheduled. Being able to schedule suspend requests from within a runtime_suspend method is useful for drivers that need to test for idleness and suspend the device all while holding a single spinlock, or for drivers that want to check for idleness by polling. Signed-off-by: Alan Stern Signed-off-by: Rafael J. Wysocki

power: support _noirq actions on device types and classes

2010-03-24T10:00:02+00:00

The new-style dev_pm_ops provide callbacks for both IRQs enabled and disabled. However, the _noirq variants were only called for buses registered with a device, not for classes and types. In order to properly use dev_pm_ops in class pcmcia_socket_class, support _noirq actions also on classes and types. Signed-off-by: Dominik Brodowski Acked-by: Rafael J. Wysocki

Driver core: create lock/unlock functions for struct device

2010-03-08T01:04:52+00:00

In the future, we are going to be changing the lock type for struct device (once we get the lockdep infrastructure properly worked out) To make that changeover easier, and to possibly burry the lock in a different part of struct device, let's create some functions to lock and unlock a device so that no out-of-core code needs to be changed in the future. This patch creates the device_lock/unlock/trylock() functions, and converts all in-tree users to them. Cc: Thomas Gleixner Cc: Jean Delvare Cc: Dave Young Cc: Ming Lei Cc: Jiri Kosina Cc: Phil Carmody Cc: Arjan van de Ven Cc: Cornelia Huck Cc: Rafael J. Wysocki Cc: Pavel Machek Cc: Len Brown Cc: Magnus Damm Cc: Alan Stern Cc: Randy Dunlap Cc: Stefan Richter Cc: David Brownell Cc: Vegard Nossum Cc: Jesse Barnes Cc: Alex Chiang Cc: Kenji Kaneshige Cc: Andrew Morton Cc: Andrew Patterson Cc: Yu Zhao Cc: Dominik Brodowski Cc: Samuel Ortiz Cc: Wolfram Sang Cc: CHENG Renquan Cc: Oliver Neukum Cc: Frans Pop Cc: David Vrabel Cc: Kay Sievers Cc: Sarah Sharp Signed-off-by: Greg Kroah-Hartman

PM: Provide generic subsystem-level callbacks

2010-03-06T20:28:37+00:00

There are subsystems whose power management callbacks only need to invoke the callbacks provided by device drivers. Still, their system sleep PM callbacks should play well with the runtime PM callbacks, so that devices suspended at run time can be left in that state for a system sleep transition. Provide a set of generic PM callbacks for such subsystems and define convenience macros for populating dev_pm_ops structures. Signed-off-by: Rafael J. Wysocki

PM: Allow device drivers to use dpm_wait()

2010-02-26T19:39:11+00:00

There are some dependencies between devices (in particular, between EHCI USB controllers and their OHCI/UHCI siblings) which are not reflected by the structure of the device tree. With synchronous suspend and resume these dependencies are taken into accout automatically, because the devices in question are always registered in the right order, but to meet these constraints with asynchronous suspend and resume the drivers of these devices will need to use dpm_wait() in their suspend/resume routines, so introduce a helper function allowing them to do that. Signed-off-by: Rafael J. Wysocki

PM: Start asynchronous resume threads upfront

2010-02-26T19:39:11+00:00

It has been shown by testing that total device resume time can be reduced significantly (by as much as 50% or more) if the async threads executing some devices' resume routines are all started before the main resume thread starts to handle the "synchronous" devices. This is a consequence of the fact that the slowest devices tend to be located at the end of dpm_list, so their resume routines are started very late. Consequently, they have to wait for all the preceding "synchronous" devices before their resume routines can be started by the main resume thread, even if they are "asynchronous". By starting their async threads upfront we effectively move those devices towards the beginning of dpm_list, without breaking their ordering with respect to their parents and children. As a result, their resume routines are started much earlier and we are able to save much more device resume time this way. Signed-off-by: Rafael J. Wysocki

PM: Add facility for advanced testing of async suspend/resume

2010-02-26T19:39:10+00:00

Add configuration switch CONFIG_PM_ADVANCED_DEBUG for compiling in extra PM debugging/testing code allowing one to access some PM-related attributes of devices from the user space via sysfs. If CONFIG_PM_ADVANCED_DEBUG is set, add sysfs attribute power/async for every device allowing the user space to access the device's power.async_suspend flag and modify it, if desired. Signed-off-by: Rafael J. Wysocki

PM: Add a switch for disabling/enabling asynchronous suspend/resume

2010-02-26T19:39:10+00:00

Add sysfs attribute /sys/power/pm_async allowing the user space to disable/enable asynchronous suspend/resume of devices. Signed-off-by: Rafael J. Wysocki