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* PM / Sleep: Warn about system time after resume with pm_traceShuah Khan2013-06-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | pm_trace uses the system's Real Time Clock (RTC) to save the magic number. The reason for this is that the RTC is the only reliably available piece of hardware during resume operations where a value can be set that will survive a reboot. Consequence is that after a resume (even if it is successful) your system clock will have a value corresponding to the magic number instead of the correct date/time! It is therefore advisable to use a program like ntp-date or rdate to reset the correct date/time from an external time source when using this trace option. There is no run-time message to warn users of the consequences of enabling pm_trace. Adding a warning message to pm_trace_store() will serve as a reminder to users to set the system date and time after resume. Signed-off-by: Shuah Khan <shuah.kh@samsung.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Sleep: Print last wakeup source on failed wakeup_count writeJulius Werner2013-06-211-0/+2
| | | | | | | | | | | | | | | | | | | Commit a938da06 introduced a useful little log message to tell users/debuggers which wakeup source aborted a suspend. However, this message is only printed if the abort happens during the in-kernel suspend path (after writing /sys/power/state). The full specification of the /sys/power/wakeup_count facility allows user-space power managers to double-check if wakeups have already happened before it actually tries to suspend (e.g. while it was running user-space pre-suspend hooks), by writing the last known wakeup_count value to /sys/power/wakeup_count. This patch changes the sysfs handler for that node to also print said log message if that write fails, so that we can figure out the offending wakeup source for both kinds of suspend aborts. Signed-off-by: Julius Werner <jwerner@chromium.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* suspend: enable freeze timeout configuration through sysLi Fei2013-02-091-0/+27
| | | | | | | | | | | | | | | | | | | | | At present, the value of timeout for freezing is 20s, which is meaningless in case that one thread is frozen with mutex locked and another thread is trying to lock the mutex, as this time of freezing will fail unavoidably. And if there is no new wakeup event registered, the system will waste at most 20s for such meaningless trying of freezing. With this patch, the value of timeout can be configured to smaller value, so such meaningless trying of freezing will be aborted in earlier time, and later freezing can be also triggered in earlier time. And more power will be saved. In normal case on mobile phone, it costs real little time to freeze processes. On some platform, it only costs about 20ms to freeze user space processes and 10ms to freeze kernel freezable threads. Signed-off-by: Liu Chuansheng <chuansheng.liu@intel.com> Signed-off-by: Li Fei <fei.li@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM: Introduce suspend state PM_SUSPEND_FREEZEZhang Rui2013-02-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PM_SUSPEND_FREEZE state is a general state that does not need any platform specific support, it equals frozen processes + suspended devices + idle processors. Compared with PM_SUSPEND_MEMORY, PM_SUSPEND_FREEZE saves less power because the system is still in a running state. PM_SUSPEND_FREEZE has less resume latency because it does not touch BIOS, and the processors are in idle state. Compared with RTPM/idle, PM_SUSPEND_FREEZE saves more power as 1. the processor has longer sleep time because processes are frozen. The deeper c-state the processor supports, more power saving we can get. 2. PM_SUSPEND_FREEZE uses system suspend code path, thus we can get more power saving from the devices that does not have good RTPM support. This state is useful for 1) platforms that do not have STR, or have a broken STR. 2) platforms that have an extremely low power idle state, which can be used to replace STR. The following describes how PM_SUSPEND_FREEZE state works. 1. echo freeze > /sys/power/state 2. the processes are frozen. 3. all the devices are suspended. 4. all the processors are blocked by a wait queue 5. all the processors idles and enters (Deep) c-state. 6. an interrupt fires. 7. a processor is woken up and handles the irq. 8. if it is a general event, a) the irq handler runs and quites. b) goto step 4. 9. if it is a real wake event, say, power button pressing, keyboard touch, mouse moving, a) the irq handler runs and activate the wakeup source b) wakeup_source_activate() notifies the wait queue. c) system starts resuming from PM_SUSPEND_FREEZE 10. all the devices are resumed. 11. all the processes are unfrozen. 12. system is back to working. Known Issue: The wakeup of this new PM_SUSPEND_FREEZE state may behave differently from the previous suspend state. Take ACPI platform for example, there are some GPEs that only enabled when the system is in sleep state, to wake the system backk from S3/S4. But we are not touching these GPEs during transition to PM_SUSPEND_FREEZE. This means we may lose some wake event. But on the other hand, as we do not disable all the Interrupts during PM_SUSPEND_FREEZE, we may get some extra "wakeup" Interrupts, that are not available for S3/S4. The patches has been tested on an old Sony laptop, and here are the results: Average Power: 1. RPTM/idle for half an hour: 14.8W, 12.6W, 14.1W, 12.5W, 14.4W, 13.2W, 12.9W 2. Freeze for half an hour: 11W, 10.4W, 9.4W, 11.3W 10.5W 3. RTPM/idle for three hours: 11.6W 4. Freeze for three hours: 10W 5. Suspend to Memory: 0.5~0.9W Average Resume Latency: 1. RTPM/idle with a black screen: (From pressing keyboard to screen back) Less than 0.2s 2. Freeze: (From pressing power button to screen back) 2.50s 3. Suspend to Memory: (From pressing power button to screen back) 4.33s >From the results, we can see that all the platforms should benefit from this patch, even if it does not have Low Power S0. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / sysfs: replace strict_str* with kstrto*Daniel Walter2012-11-151-1/+1
| | | | | | | | | | | Replace strict_strtoul() with kstrtoul() in pm_async_store() and pm_qos_power_write(). [rjw: Modified subject and changelog.] Signed-off-by: Daniel Walter <sahne@0x90.at> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Sleep: Separate printing suspend times from initcall_debugRafael J. Wysocki2012-07-011-32/+44
| | | | | | | | | | | | | | Change the behavior of the newly introduced /sys/power/pm_print_times attribute so that its initial value depends on initcall_debug, but setting it to 0 will cause device suspend/resume times not to be printed, even if initcall_debug has been set. This way, the people who use initcall_debug for reasons other than PM debugging will be able to switch the suspend/resume times printing off, if need be. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* PM / Sleep: add knob for printing device resume timesSameer Nanda2012-07-011-0/+33
| | | | | | | | | | | Added a new knob called /sys/power/pm_print_times. Setting it to 1 enables printing of time taken by devices to suspend and resume. Setting it to 0 disables this printing (unless overridden by initcall_debug kernel command line option). Signed-off-by: Sameer Nanda <snanda@chromium.org> Acked-by: Greg KH <gregkh@linuxfoundation.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Sleep: Fix a mistake in a conditional in autosleep_store()Arve Hjønnevåg2012-05-051-1/+1
| | | | | | | | | | The condition check in autosleep_store() is incorrect and prevents /sys/power/autosleep from working as advertised. Fix that. [rjw: Added the changelog.] Signed-off-by: Arve Hjønnevåg <arve@android.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Sleep: Add user space interface for manipulating wakeup sources, v3Rafael J. Wysocki2012-05-011-0/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Android allows user space to manipulate wakelocks using two sysfs file located in /sys/power/, wake_lock and wake_unlock. Writing a wakelock name and optionally a timeout to the wake_lock file causes the wakelock whose name was written to be acquired (it is created before is necessary), optionally with the given timeout. Writing the name of a wakelock to wake_unlock causes that wakelock to be released. Implement an analogous interface for user space using wakeup sources. Add the /sys/power/wake_lock and /sys/power/wake_unlock files allowing user space to create, activate and deactivate wakeup sources, such that writing a name and optionally a timeout to wake_lock causes the wakeup source of that name to be activated, optionally with the given timeout. If that wakeup source doesn't exist, it will be created and then activated. Writing a name to wake_unlock causes the wakeup source of that name, if there is one, to be deactivated. Wakeup sources created with the help of wake_lock that haven't been used for more than 5 minutes are garbage collected and destroyed. Moreover, there can be only WL_NUMBER_LIMIT wakeup sources created with the help of wake_lock present at a time. The data type used to track wakeup sources created by user space is called "struct wakelock" to indicate the origins of this feature. This version of the patch includes an rbtree manipulation fix from John Stultz. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: NeilBrown <neilb@suse.de>
* PM / Sleep: Implement opportunistic sleep, v2Rafael J. Wysocki2012-05-011-19/+100
| | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a mechanism by which the kernel can trigger global transitions to a sleep state chosen by user space if there are no active wakeup sources. It consists of a new sysfs attribute, /sys/power/autosleep, that can be written one of the strings returned by reads from /sys/power/state, an ordered workqueue and a work item carrying out the "suspend" operations. If a string representing the system's sleep state is written to /sys/power/autosleep, the work item triggering transitions to that state is queued up and it requeues itself after every execution until user space writes "off" to /sys/power/autosleep. That work item enables the detection of wakeup events using the functions already defined in drivers/base/power/wakeup.c (with one small modification) and calls either pm_suspend(), or hibernate() to put the system into a sleep state. If a wakeup event is reported while the transition is in progress, it will abort the transition and the "system suspend" work item will be queued up again. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: NeilBrown <neilb@suse.de>
* PM / Sleep: Make enter_state() in kernel/power/suspend.c staticRafael J. Wysocki2012-02-171-5/+3
| | | | | | | | | | The enter_state() function in kernel/power/suspend.c should be static and state_store() in kernel/power/suspend.c should call pm_suspend() instead of it, so make that happen (which also reduces code duplication related to suspend statistics). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
* PM / Suspend: Avoid code duplication in suspend statistics updateMarcos Paulo de Souza2012-02-091-5/+1
| | | | | | | | | | | | | | | | | | The code if (error) { suspend_stats.fail++; dpm_save_failed_errno(error); } else suspend_stats.success++; Appears in the kernel/power/main.c and kernel/power/suspend.c. This patch just creates a new function to avoid duplicated code. Suggested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Marcos Paulo de Souza <marcos.mage@gmail.com> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Sleep: Introduce "late suspend" and "early resume" of devicesRafael J. Wysocki2012-01-291-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current device suspend/resume phases during system-wide power transitions appear to be insufficient for some platforms that want to use the same callback routines for saving device states and related operations during runtime suspend/resume as well as during system suspend/resume. In principle, they could point their .suspend_noirq() and .resume_noirq() to the same callback routines as their .runtime_suspend() and .runtime_resume(), respectively, but at least some of them require device interrupts to be enabled while the code in those routines is running. It also makes sense to have device suspend-resume callbacks that will be executed with runtime PM disabled and with device interrupts enabled in case someone needs to run some special code in that context during system-wide power transitions. Apart from this, .suspend_noirq() and .resume_noirq() were introduced as a workaround for drivers using shared interrupts and failing to prevent their interrupt handlers from accessing suspended hardware. It appears to be better not to use them for other porposes, or we may have to deal with some serious confusion (which seems to be happening already). For the above reasons, introduce new device suspend/resume phases, "late suspend" and "early resume" (and analogously for hibernation) whose callback will be executed with runtime PM disabled and with device interrupts enabled and whose callback pointers generally may point to runtime suspend/resume routines. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Kevin Hilman <khilman@ti.com>
* PM / Sleep: Replace mutex_[un]lock(&pm_mutex) with [un]lock_system_sleep()Srivatsa S. Bhat2011-12-081-2/+2
| | | | | | | | | | | | Using [un]lock_system_sleep() is safer than directly using mutex_[un]lock() on 'pm_mutex', since the latter could lead to freezing failures. Hence convert all the present users of mutex_[un]lock(&pm_mutex) to use these safe APIs instead. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Reviewed-by: Simon Horman <horms@verge.net.au> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Fix indentation and remove extraneous whitespaces in kernel/power/main.cSrivatsa S. Bhat2011-11-231-3/+3
| | | | | | | | | | | Lack of proper indentation of the goto statement decreases the readability of code significantly. In fact, this made me look twice at the code to check whether it really does what it should be doing. Fix this. And in the same file, there are some extra whitespaces. Get rid of them too. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Suspend: Fix bug in suspend statistics updateSrivatsa S. Bhat2011-11-191-1/+2
| | | | | | | | | | | | | After commit 2a77c46de1e3dace73745015635ebbc648eca69c (PM / Suspend: Add statistics debugfs file for suspend to RAM) a missing pair of braces inside the state_store() function causes even invalid arguments to suspend to be wrongly treated as failed suspend attempts. Fix this. [rjw: Put the hash/subject of the buggy commit into the changelog.] Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructurePaul Gortmaker2011-10-311-0/+1
| | | | | | | | | | These files were getting <linux/module.h> via an implicit non-obvious path, but we want to crush those out of existence since they cost time during compiles of processing thousands of lines of headers for no reason. Give them the lightweight header that just contains the EXPORT_SYMBOL infrastructure. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* PM: Fix build issue in main.c for CONFIG_PM_SLEEP unsetRafael J. Wysocki2011-10-161-2/+2
| | | | | | | Suspend statistics should depend on CONFIG_PM_SLEEP, so make that happen. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Suspend: Add statistics debugfs file for suspend to RAMShuoX Liu2011-10-161-0/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <shuox.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Improve error code of pm_notifier_call_chain()Akinobu Mita2011-07-151-2/+3
| | | | | | | | | | This enables pm_notifier_call_chain() to get the actual error code in the callback rather than always assume -EINVAL by converting all PM notifier calls to return encapsulate error code with notifier_from_errno(). Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Hibernate: Add sysfs knob to control size of memory for driversRafael J. Wysocki2011-05-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Martin reports that on his system hibernation occasionally fails due to the lack of memory, because the radeon driver apparently allocates too much of it during the device freeze stage. It turns out that the amount of memory allocated by radeon during hibernation (and presumably during system suspend too) depends on the utilization of the GPU (e.g. hibernating while there are two KDE 4 sessions with compositing enabled causes radeon to allocate more memory than for one KDE 4 session). In principle it should be possible to use image_size to make the memory preallocation mechanism free enough memory for the radeon driver, but in practice it is not easy to guess the right value because of the way the preallocation code uses image_size. For this reason, it seems reasonable to allow users to control the amount of memory reserved for driver allocations made after the hibernate preallocation, which currently is constant and amounts to 1 MB. Introduce a new sysfs file, /sys/power/reserved_size, whose value will be used as the amount of memory to reserve for the post-preallocation reservations made by device drivers, in bytes. For backwards compatibility, set its default (and initial) value to the currently used number (1 MB). References: https://bugzilla.kernel.org/show_bug.cgi?id=34102 Reported-and-tested-by: Martin Steigerwald <Martin@Lichtvoll.de> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* Fix common misspellingsLucas De Marchi2011-03-311-1/+1
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* PM: Drop pm_flags that is not necessaryRafael J. Wysocki2011-03-151-13/+0
| | | | | | | | | | | | | | The variable pm_flags is used to prevent APM from being enabled along with ACPI, which would lead to problems. However, acpi_init() is always called before apm_init() and after acpi_init() has returned, it is known whether or not ACPI will be used. Namely, if acpi_disabled is not set after acpi_init() has returned, this means that ACPI is enabled. Thus, it is sufficient to check acpi_disabled in apm_init() to prevent APM from being enabled in parallel with ACPI. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Len Brown <len.brown@intel.com>
* PM / ACPI: Remove references to pm_flags from bus.cRafael J. Wysocki2011-03-151-1/+11
| | | | | | | | | If direct references to pm_flags are removed from drivers/acpi/bus.c, CONFIG_ACPI will not need to depend on CONFIG_PM any more. Make that happen. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Len Brown <len.brown@intel.com>
* workqueue, freezer: unify spelling of 'freeze' + 'able' to 'freezable'Tejun Heo2011-02-161-1/+1
| | | | | | | | | | | | | | | | | There are two spellings in use for 'freeze' + 'able' - 'freezable' and 'freezeable'. The former is the more prominent one. The latter is mostly used by workqueue and in a few other odd places. Unify the spelling to 'freezable'. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Dmitry Torokhov <dtor@mail.ru> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Alex Dubov <oakad@yahoo.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Steven Whitehouse <swhiteho@redhat.com>
* PM: Add sysfs attr for rechecking dev hash from PM traceJames Hogan2010-10-171-0/+18
| | | | | | | | | | | | | | | If the device which fails to resume is part of a loadable kernel module it won't be checked at startup against the magic number stored in the RTC. Add a read-only sysfs attribute /sys/power/pm_trace_dev_match which contains a list of newline separated devices (usually just the one) which currently match the last magic number. This allows the device which is failing to resume to be found after the modules are loaded again. Signed-off-by: James Hogan <james@albanarts.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Wakeup: Introduce wakeup source objects and event statistics (v3)Rafael J. Wysocki2010-10-171-4/+4
| | | | | | | | | | | | | | | | | | | | | | Introduce struct wakeup_source for representing system wakeup sources within the kernel and for collecting statistics related to them. Make the recently introduced helper functions pm_wakeup_event(), pm_stay_awake() and pm_relax() use struct wakeup_source objects internally, so that wakeup statistics associated with wakeup devices can be collected and reported in a consistent way (the definition of pm_relax() is changed, which is harmless, because this function is not called directly by anyone yet). Introduce new wakeup-related sysfs device attributes in /sys/devices/.../power for reporting the device wakeup statistics. Change the global wakeup events counters event_count and events_in_progress into atomic variables, so that it is not necessary to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake() and pm_relax(), which should allow us to avoid lock contention in these functions on SMP systems with many wakeup devices. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
* PM / Hibernate: Make default image size depend on total RAM sizeRafael J. Wysocki2010-10-171-0/+1
| | | | | | | | | | | The default hibernation image size is currently hard coded and euqal to 500 MB, which is not a reasonable default on many contemporary systems. Make it equal 2/5 of the total RAM size (this is slightly below the maximum, i.e. 1/2 of the total RAM size, and seems to be generally suitable). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Tested-by: M. Vefa Bicakci <bicave@superonline.com>
* PM / Runtime: Use alloc_workqueue() for creating the PM workqueueRafael J. Wysocki2010-10-171-1/+1
| | | | | | | | | | | Although we need the PM workqueue to be freezable, we don't need it to be singlethread. Also, the number of concurrent work items running on a single CPU need not be constrained. For these reasons use alloc_workqueue() directly, with suitable arguments, instead of create_freezeable_workqueue(), to create the runtime PM workqueue. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Tejun Heo <tj@kernel.org>
* PM: Make it possible to avoid races between wakeup and system sleepRafael J. Wysocki2010-07-191-0/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One of the arguments during the suspend blockers discussion was that the mainline kernel didn't contain any mechanisms making it possible to avoid races between wakeup and system suspend. Generally, there are two problems in that area. First, if a wakeup event occurs exactly when /sys/power/state is being written to, it may be delivered to user space right before the freezer kicks in, so the user space consumer of the event may not be able to process it before the system is suspended. Second, if a wakeup event occurs after user space has been frozen, it is not generally guaranteed that the ongoing transition of the system into a sleep state will be aborted. To address these issues introduce a new global sysfs attribute, /sys/power/wakeup_count, associated with a running counter of wakeup events and three helper functions, pm_stay_awake(), pm_relax(), and pm_wakeup_event(), that may be used by kernel subsystems to control the behavior of this attribute and to request the PM core to abort system transitions into a sleep state already in progress. The /sys/power/wakeup_count file may be read from or written to by user space. Reads will always succeed (unless interrupted by a signal) and return the current value of the wakeup events counter. Writes, however, will only succeed if the written number is equal to the current value of the wakeup events counter. If a write is successful, it will cause the kernel to save the current value of the wakeup events counter and to abort the subsequent system transition into a sleep state if any wakeup events are reported after the write has returned. [The assumption is that before writing to /sys/power/state user space will first read from /sys/power/wakeup_count. Next, user space consumers of wakeup events will have a chance to acknowledge or veto the upcoming system transition to a sleep state. Finally, if the transition is allowed to proceed, /sys/power/wakeup_count will be written to and if that succeeds, /sys/power/state will be written to as well. Still, if any wakeup events are reported to the PM core by kernel subsystems after that point, the transition will be aborted.] Additionally, put a wakeup events counter into struct dev_pm_info and make these per-device wakeup event counters available via sysfs, so that it's possible to check the activity of various wakeup event sources within the kernel. To illustrate how subsystems can use pm_wakeup_event(), make the low-level PCI runtime PM wakeup-handling code use it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: markgross <markgross@thegnar.org> Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
* PM: Add a switch for disabling/enabling asynchronous suspend/resumeRafael J. Wysocki2010-02-261-1/+30
| | | | | | | 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 <rjw@sisk.pl>
* PM / Runtime: Export the PM runtime workqueueAlan Stern2009-12-061-0/+1
| | | | | | | | This patch (as1306) exports the PM runtime workqueue for use by loadable modules. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Introduce core framework for run-time PM of I/O devices (rev. 17)Rafael J. Wysocki2009-08-231-0/+17
| | | | | | | | | | | | | | | Introduce a core framework for run-time power management of I/O devices. Add device run-time PM fields to 'struct dev_pm_info' and device run-time PM callbacks to 'struct dev_pm_ops'. Introduce a run-time PM workqueue and define some device run-time PM helper functions at the core level. Document all these things. Special thanks to Alan Stern for his help with the design and multiple detailed reviews of the pereceding versions of this patch and to Magnus Damm for testing feedback. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@igel.co.jp>
* PM: Separate suspend to RAM functionality from coreRafael J. Wysocki2009-06-121-503/+0
| | | | | | | | | | | | Move the suspend to RAM and standby code from kernel/power/main.c to two separate files, kernel/power/suspend.c containing the basic functions and kernel/power/suspend_test.c containing the automatic suspend test facility based on the RTC clock alarm. There are no changes in functionality related to these modifications. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz>
* PM/Suspend: Do not shrink memory before suspendRafael J. Wysocki2009-06-121-19/+1
| | | | | | | | | Remove the shrinking of memory from the suspend-to-RAM code, where it is not really necessary. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@tuxonice.net> Acked-by: Wu Fengguang <fengguang.wu@intel.com>
* PM core: rename suspend and resume functionsAlan Stern2009-06-121-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch (as1241) renames a bunch of functions in the PM core. Rather than go through a boring list of name changes, suffice it to say that in the end we have a bunch of pairs of functions: device_resume_noirq dpm_resume_noirq device_resume dpm_resume device_complete dpm_complete device_suspend_noirq dpm_suspend_noirq device_suspend dpm_suspend device_prepare dpm_prepare in which device_X does the X operation on a single device and dpm_X invokes device_X for all devices in the dpm_list. In addition, the old dpm_power_up and device_resume_noirq have been combined into a single function (dpm_resume_noirq). Lastly, dpm_suspend_start and dpm_resume_end are the renamed versions of the former top-level device_suspend and device_resume routines. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Rename device_power_down/up()Magnus Damm2009-06-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | Rename the functions performing "_noirq" dev_pm_ops operations from device_power_down() and device_power_up() to device_suspend_noirq() and device_resume_noirq(). The new function names are chosen to show that the functions are responsible for calling the _noirq() versions to finalize the suspend/resume operation. The current function names do not perform power down/up anymore so the names may be misleading. Global function renames: - device_power_down() -> device_suspend_noirq() - device_power_up() -> device_resume_noirq() Static function renames: - suspend_device_noirq() -> __device_suspend_noirq() - resume_device_noirq() -> __device_resume_noirq() Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Len Brown <lenb@kernel.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Do not hold dpm_list_mtx while disabling/enabling nonboot CPUsRafael J. Wysocki2009-05-241-6/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We shouldn't hold dpm_list_mtx while executing [disable|enable]_nonboot_cpus(), because theoretically this may lead to a deadlock as shown by the following example (provided by Johannes Berg): CPU 3 CPU 2 CPU 1 suspend/hibernate something: rtnl_lock() device_pm_lock() -> mutex_lock(&dpm_list_mtx) mutex_lock(&dpm_list_mtx) linkwatch_work -> rtnl_lock() disable_nonboot_cpus() -> flush CPU 3 workqueue Fortunately, device drivers are supposed to stop any activities that might lead to the registration of new device objects way before disable_nonboot_cpus() is called, so it shouldn't be necessary to hold dpm_list_mtx over the entire late part of device suspend and early part of device resume. Thus, during the late suspend and the early resume of devices acquire dpm_list_mtx only when dpm_list is going to be traversed and release it right after that. This patch is reported to fix the regressions tracked as http://bugzilla.kernel.org/show_bug.cgi?id=13245. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Miles Lane <miles.lane@gmail.com> Tested-by: Ming Lei <tom.leiming@gmail.com>
* PM/Suspend: Introduce two new platform callbacks to avoid breakageRafael J. Wysocki2009-04-191-7/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 900af0d973856d6feb6fc088c2d0d3fde57707d3 (PM: Change suspend code ordering) changed the ordering of suspend code in such a way that the platform .prepare() callback is now executed after the device drivers' late suspend callbacks have run. Unfortunately, this turns out to break ARM platforms that need to talk via I2C to power control devices during the .prepare() callback. For this reason introduce two new platform suspend callbacks, .prepare_late() and .wake(), that will be called just prior to disabling non-boot CPUs and right after bringing them back on line, respectively, and use them instead of .prepare() and .finish() for ACPI suspend. Make the PM core execute the .prepare() and .finish() platform suspend callbacks where they were executed previously (that is, right after calling the regular suspend methods provided by device drivers and right before executing their regular resume methods, respectively). It is not necessary to make analogous changes to the hibernation code and data structures at the moment, because they are only used by ACPI platforms. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reported-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Len Brown <len.brown@intel.com>
* PM: Change suspend code orderingRafael J. Wysocki2009-03-301-16/+22
| | | | | | | | | | | | | | | | Change the ordering of the suspend core code so that the platform "prepare" callback is executed and the nonboot CPUs are disabled after calling device drivers' "late suspend" methods. This change will allow us to rework the PCI PM core so that the power state of devices is changed in the "late" phase of suspend (and analogously in the "early" phase of resume), which in turn will allow us to avoid the race condition where a device using shared interrupts is put into a low power state with interrupts enabled and then an interrupt (for another device) comes in and confuses its driver. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Ingo Molnar <mingo@elte.hu>
* PM: Rework handling of interrupts during suspend-resumeRafael J. Wysocki2009-03-301-6/+11
| | | | | | | | | | | | | | | | | | | | Use the functions introduced in by the previous patch, suspend_device_irqs(), resume_device_irqs() and check_wakeup_irqs(), to rework the handling of interrupts during suspend (hibernation) and resume. Namely, interrupts will only be disabled on the CPU right before suspending sysdevs, while device drivers will be prevented from receiving interrupts, with the help of the new helper function, before their "late" suspend callbacks run (and analogously during resume). In addition, since the device interrups are now disabled before the CPU has turned all interrupts off and the CPU will ACK the interrupts setting the IRQ_PENDING bit for them, check in sysdev_suspend() if any wake-up interrupts are pending and abort suspend if that's the case. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Ingo Molnar <mingo@elte.hu>
* PM: Split up sysdev_[suspend|resume] from device_power_[down|up]Rafael J. Wysocki2009-02-221-2/+6
| | | | | | | | | | | Move the sysdev_suspend/resume from the callee to the callers, with no real change in semantics, so that we can rework the disabling of interrupts during suspend/hibernation. This is based on an earlier patch from Linus. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* PM: Fix compilation warning in kernel/power/main.cRafael J. Wysocki2009-01-161-13/+13
| | | | | | | | Reorder the code in kernel/power/main.c to fix compilation warning triggered by unsetting CONFIG_SUSPEND. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
* pm: struct device - replace bus_id with dev_name(), dev_set_name()Kay Sievers2009-01-061-3/+3
| | | | | Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* tracing: allow tracing of suspend/resume & hibernation code againIngo Molnar2008-11-231-4/+1
| | | | | | | | | | | | | | | | | Impact: widen function-tracing to suspend+resume (and hibernation) sequences Now that the ftrace kernel thread is gone, we can allow tracing during suspend/resume again. So revert these two commits: f42ac38c5 "ftrace: disable tracing for suspend to ram" 41108eb10 "ftrace: disable tracing for hibernation" This should be tested very carefully, as it could interact with altneratives instruction patching, etc. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* suspend: use WARN not WARN_ON to print the messageArjan van de Ven2008-11-181-1/+1
| | | | | | | | | | By using WARN(), kerneloops.org can collect which component is causing the delay and make statistics about that. suspend_test_finish() is currently the number 2 item but unless we can collect who's causing it we're not going to be able to fix the hot topic ones.. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pm: rework disabling of user mode helpers during suspend/hibernationRafael J. Wysocki2008-10-161-0/+7
| | | | | | | | | | | | | | | | | | | | | We currently use a PM notifier to disable user mode helpers before suspend and hibernation and to re-enable them during resume. However, this is not an ideal solution, because if any drivers want to upload firmware into memory before suspend, they have to use a PM notifier for this purpose and there is no guarantee that the ordering of PM notifiers will be as expected (ie. the notifier that disables user mode helpers has to be run after the driver's notifier used for uploading the firmware). For this reason, it seems better to move the disabling and enabling of user mode helpers to separate functions that will be called by the PM core as necessary. [akpm@linux-foundation.org: remove unneeded ifdefs] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Alan Stern <stern@rowland.harvard.edu> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ftrace: disable tracing for suspend to ramSteven Rostedt2008-08-271-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I've been painstakingly debugging the issue with suspend to ram and ftraced. The 2.6.28 code does not have this issue, but since the mcount recording is not going to be in 27, this must be solved for the ftrace daemon version. The resume from suspend to ram would reboot because it was triple faulting. Debugging further, I found that calling the mcount function itself was not an issue, but it would fault when it incremented preempt_count. preempt_count is on the tasks info structure that is on the low memory address of the task's stack. For some reason, it could not write to it. Resuming out of suspend to ram does quite a lot of funny tricks to get to work, so it is not surprising at all that simply doing a preempt_disable() would cause a fault. Thanks to Rafael for suggesting to add a "while (1);" to find the place in resuming that is causing the fault. I would place the loop somewhere in the code, compile and reboot and see if it would either reboot (hit the fault) or simply hang (hit the loop). Doing this over and over again, I narrowed it down that it was happening in enable_nonboot_cpus. At this point, I found that it is easier to simply disable tracing around the suspend code, instead of searching for the particular function that can not handle doing a preempt_disable. This patch disables the tracer as it suspends and reenables it on resume. I tested this patch on my Laptop, and it can resume fine with the patch. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pm selftest: rtc paranoiaDavid Brownell2008-07-261-0/+7
| | | | | | | | | | Cope with a quirk of some RTCs (notably ACPI ones) which aren't guaranteed to implement oneshot behavior when they woke the system from sleeep: forcibly disable the alarm, just in case. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pm: boot time suspend selftestDavid Brownell2008-07-241-1/+193
| | | | | | | | | | | | | | | | | | | | | | | | | | | Boot-time test for system suspend states (STR or standby). The generic RTC framework triggers wakeup alarms, which are used to exit those states. - Measures some aspects of suspend time ... this uses "jiffies" until someone converts it to use a timebase that works properly even while timer IRQs are disabled. - Triggered by a command line parameter. By default nothing even vaguely troublesome will happen, but "test_suspend=mem" will give you a brief STR test during system boot. (Or you may need to use "test_suspend=standby" instead, if your hardware needs that.) This isn't without problems. It fires early enough during boot that for example both PCMCIA and MMC stacks have misbehaved. The workaround in those cases was to boot without such media cards inserted. [matthltc@us.ibm.com: fix compile failure in boot time suspend selftest] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Machek <pavel@suse.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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