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* PM / runtime: Drop children check from __pm_runtime_set_status()Rafael J. Wysocki2017-11-161-2/+1
| | | | | | | | | | | | | | | | | | | | The check for "active" children in __pm_runtime_set_status(), when trying to set the parent device status to "suspended", doesn't really make sense, because in fact it is not invalid to set the status of a device with runtime PM disabled to "suspended" in any case. It is invalid to enable runtime PM for a device with its status set to "suspended" while its child_count reference counter is nonzero, but the check in __pm_runtime_set_status() doesn't really cover that situation. For this reason, drop the children check from __pm_runtime_set_status() and add a check against child_count reference counters of "suspended" devices to pm_runtime_enable(). Fixes: a8636c89648a (PM / Runtime: Don't allow to suspend a device with an active child) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Johan Hovold <johan@kernel.org>
* Documentation: fix driver-api doc refsTom Saeger2017-10-121-1/+1
| | | | | | | | Make driver-api document refs valid. Signed-off-by: Tom Saeger <tom.saeger@oracle.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* PM / runtime: Document new pm_runtime_set_suspended() constraintJohan Hovold2017-07-271-1/+2
| | | | | | | | | | | | | Since commit a8636c89648a (PM / Runtime: Don't allow to suspend a device with an active child) it is no longer permitted to set RPM_SUSPENDED state for a device with active children unless power.ignore_children is set. Update the documentation to reflect this. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / core: Drop run_wake flag from struct dev_pm_infoRafael J. Wysocki2017-06-281-5/+2
| | | | | | | | | | | | | | | | | | The run_wake flag in struct dev_pm_info is used to indicate whether or not the device is capable of generating remote wakeup signals at run time (or in the system working state), but the distinction between runtime remote wakeup and system wakeup signaling has always been rather artificial. The only practical reason for it to exist at the core level was that ACPI and PCI treated those two cases differently, but that's not the case any more after recent changes. For this reason, get rid of the run_wake flag and, when applicable, use device_set_wakeup_capable() and device_can_wakeup() instead of device_set_run_wake() and device_run_wake(), respectively. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
* PM / runtime: Document autosuspend-helper side effectsJohan Hovold2017-04-191-3/+11
| | | | | | | | | | | | | | | Document the fact that the autosuspend delay and enable helpers may change the power.usage_count and resume or suspend a device depending on the values of power.autosuspend_delay and power.use_autosuspend. Note that this means that a driver must disable autosuspend before disabling runtime pm on probe errors and on driver unbind if the device is to be suspended upon return (as a negative delay may otherwise keep the device resumed). Signed-off-by: Johan Hovold <johan@kernel.org> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / runtime: Fix autosuspend documentationJohan Hovold2017-04-191-3/+2
| | | | | | | | | | | | | | | | | | | | | | Update the autosuspend documentation which claimed that the autosuspend delay is not taken into account when using the non-autosuspend helper functions, something which is no longer true since commit d66e6db28df3 ("PM / Runtime: Respect autosuspend when idle triggers suspend"). This specifically means that drivers must now disable autosuspend before disabling runtime pm in probe error paths and remove callbacks if pm_runtime_put_sync was being used to suspend the device before returning. (If an idle callback can prevent suspend, pm_runtime_put_sync_suspend must be used instead of pm_runtime_put_sync as before.) Also remove the claim that the autosuspend helpers behave "just like the non-autosuspend counterparts", something which have never really been true as some of the latter use idle notifications. Signed-off-by: Johan Hovold <johan@kernel.org> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / runtime: Fix some typosChristophe Jaillet2017-02-231-3/+3
| | | | | | Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* docs: fix locations of several documents that got movedMauro Carvalho Chehab2016-10-241-1/+1
| | | | | | | | The previous patch renamed several files that are cross-referenced along the Kernel documentation. Adjust the links to point to the right places. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
* PM / runtime: Document steps for device removalKrzysztof Kozlowski2016-04-051-0/+4
| | | | | | | | | Put a reminder that during device removal drivers should revert all PM runtime changes from the probe. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / runtime: Add new helper for conditional usage count incrementationRafael J. Wysocki2015-12-211-0/+6
| | | | | | | | | | | | | | | | Introduce a new runtime PM function, pm_runtime_get_if_in_use(), that will increment the device's runtime PM usage counter and return 1 if its status is RPM_ACTIVE and its usage counter is greater than 0 at the same time (0 will be returned otherwise). This is useful for things that should only be done if the device is active (from the runtime PM perspective) and used by somebody (as indicated by the usage counter) already and they are not worth bothering otherwise. Requested-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / sleep: Allow devices without runtime PM to do direct-completeAlan Stern2015-07-211-4/+0
| | | | | | | | | | | | | | | Don't unset the direct_complete flag on devices that have runtime PM disabled, if they are runtime suspended. This is needed because otherwise ancestor devices wouldn't be able to do direct_complete without adding runtime PM support to all its descendants. Also removes pm_runtime_suspended_if_enabled() because it's now unused. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / runtime: add note about re-calling in during device probe()Ben Dooks2015-05-131-0/+6
| | | | | | | | | | | | The sh_eth driver has come up with an issue where the runtime_pm code suspends it during the probe() method due to the network device registration re-calling into the driver. Add a note about this into the documentation. Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-armLinus Torvalds2014-12-121-0/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: "The major updates included in this update are: - Clang compatible stack pointer accesses by Behan Webster. - SA11x0 updates from Dmitry Eremin-Solenikov. - kgdb handling of breakpoints with read-only text/modules - Support for Privileged-no-execute feature on ARMv7 to prevent userspace code execution by the kernel. - AMBA primecell bus handling of irq-safe runtime PM - Unwinding support for memset/memzero/memmove/memcpy functions - VFP fixes for Krait CPUs and improvements in detecting the VFP architecture - A number of code cleanups (using pr_*, removing or reducing the severity of a couple of kernel messages, splitting ftrace asm code out to a separate file, etc.) - Add machine name to stack dump output" * 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (62 commits) ARM: 8247/2: pcmcia: sa1100: make use of device clock ARM: 8246/2: pcmcia: sa1111: provide device clock ARM: 8245/1: pcmcia: soc-common: enable/disable socket clocks ARM: 8244/1: fbdev: sa1100fb: make use of device clock ARM: 8243/1: sa1100: add a clock alias for sa1111 pcmcia device ARM: 8242/1: sa1100: add cpu clock ARM: 8221/1: PJ4: allow building in Thumb-2 mode ARM: 8234/1: sa1100: reorder IRQ handling code ARM: 8233/1: sa1100: switch to hwirq usage ARM: 8232/1: sa1100: merge GPIO multiplexer IRQ to "normal" irq domain ARM: 8231/1: sa1100: introduce irqdomains support ARM: 8230/1: sa1100: shift IRQs by one ARM: 8229/1: sa1100: replace irq numbers with names in irq driver ARM: 8228/1: sa1100: drop entry-macro.S ARM: 8227/1: sa1100: switch to MULTI_IRQ_HANDLER ARM: 8241/1: Update processor_modes for hyp and monitor mode ARM: 8240/1: MCPM: document mcpm_sync_init() ARM: 8239/1: Introduce {set,clear}_pte_bit ARM: 8238/1: mm: Refine set_memory_* functions ARM: 8237/1: fix flush_pfn_alias ...
| * ARM: 8199/1: PM / Runtime: Add getter for querying the IRQ safe option v12Krzysztof Kozlowski2014-11-171-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a simple getter pm_runtime_is_irq_safe() for querying whether runtime PM IRQ safe was set or not. Various bus drivers implementing runtime PM may use choose to suspend differently based on IRQ safeness status of child driver (e.g. do not unprepare the clock if IRQ safe is not set). Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* | Documentation: power: Fix typo in Documentation/powerMasanari Iida2014-11-081-3/+3
|/ | | | | | | This patch fix spelling typos found in Documentation/power. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
*-. Merge branches 'pnp', 'powercap', 'pm-runtime' and 'pm-opp'Rafael J. Wysocki2014-06-031-9/+11
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * pnp: MAINTAINERS: Remove Bjorn Helgaas as PNP maintainer PNP / resources: remove positive test on unsigned values * powercap: powercap / RAPL: add new CPU IDs powercap / RAPL: further relax energy counter checks * pm-runtime: PM / runtime: Update documentation to reflect the current code flow * pm-opp: PM / OPP: discard duplicate OPPs PM / OPP: Make OPP invisible to users in Kconfig PM / OPP: fix incorrect OPP count handling in of_init_opp_table
| | * PM / runtime: Update documentation to reflect the current code flowRafael J. Wysocki2014-05-161-9/+11
| |/ | | | | | | | | | | | | | | | | The runtime PM documentation in runtime_pm.txt has not been updated after some changes to the system suspend and resume core code, so update it to reflect the current code flow. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu>
* | PM / sleep: Update device PM documentation to cover direct_completeRafael J. Wysocki2014-05-161-0/+17
|/ | | | | | | | | Update the device PM documentation in devices.txt and runtime_pm.txt to reflect the changes in the system suspend and resume handling related to the introduction of the new power.direct_complete flag. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu>
* PM / Runtime: s/foo_process_requests/foo_process_next_request/Geert Uytterhoeven2014-03-261-1/+1
| | | | | | | The example uses foo_process_next_request() everywhere else. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: GENERIC_SUBSYS_PM_OPS is goneGeert Uytterhoeven2014-03-261-7/+4
| | | | | | | | Update the documentation for the removal of GENERIC_SUBSYS_PM_OPS in commit 90363ddf0a1a4dccfbb8d0c10b8f488bc7fa69f8 ("PM: Drop generic_subsys_pm_ops") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: Correct documented return values for generic PM callbacksGeert Uytterhoeven2014-03-261-2/+2
| | | | | | | | | | As of commit 05aa55dddb9ee4045c320661068bea78dad6a6e5 ("PM / Runtime: Lenient generic runtime pm callbacks"), the generic power management callbacks pm_generic_runtime_suspend() and pm_generic_runtime_resume() return 0, not -EINVAL, if the device doesn't provide its own callbacks. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: Split line longer than 80 charactersGeert Uytterhoeven2014-03-261-5/+5
| | | | | Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: dev_pm_info.runtime_error is signedGeert Uytterhoeven2014-03-261-1/+1
| | | | | | | | dev_pm_info.runtime_error has always been a signed int, to store a signed error code. Correct the documentation. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: Update documentation around probe|remove|suspendUlf Hansson2013-11-121-8/+6
| | | | | | | | PM core and driver core has changed some behavior regarding use of runtime PM. Update the documentation accordingly. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: Respect autosuspend when idle triggers suspendUlf Hansson2013-10-161-6/+8
| | | | | | | | | | | | | | | | | | | | | For devices which don't have a .runtime_idle() callback or if it returns 0, rpm_idle() will end up in triggering a call to rpm_suspend(), thus trying to carry out a runtime suspend directly from runtime_idle(). In the above situation we want to respect devices which has enabled autosuspend, we therfore append the flag sent to rpm_suspend with RPM_AUTO. Do note that drivers still needs to update the device last busy mark, to control the delay for this circumstance. Updated runtime PM documentation accordingly. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Kevin Hilman <khilman@linaro.org> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: Update .runtime_idle() callback documentationAlan Stern2013-06-031-5/+10
| | | | | | | | | Runtime PM documentation needs to be updated after the previous change of the rpm_idle() behavior, so modify it as appropriate. [rjw: Subject and changelog] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / Runtime: Rework the "runtime idle" helper routineRafael J. Wysocki2013-06-031-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | The "runtime idle" helper routine, rpm_idle(), currently ignores return values from .runtime_idle() callbacks executed by it. However, it turns out that many subsystems use pm_generic_runtime_idle() which checks the return value of the driver's callback and executes pm_runtime_suspend() for the device unless that value is not 0. If that logic is moved to rpm_idle() instead, pm_generic_runtime_idle() can be dropped and its users will not need any .runtime_idle() callbacks any more. Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle() routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and ata_port_runtime_idle(), respectively, as well as a few drivers' ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has been returned by the .runtime_idle() callback executed by it. To reduce overall code bloat, make the changes described above. Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Tested-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Kevin Hilman <khilman@linaro.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Alan Stern <stern@rowland.harvard.edu>
* PM / Runtime: Add new helper function: pm_runtime_active()ShuoX Liu2013-01-261-0/+4
| | | | | | | | | | | | | This boolean function simply returns whether or not the runtime status of the device is 'active'. The typical scenario is driver calls pm_runtime_get firstly, then check pm_runtime_active in atomic environment. Also add entry to Documentation/power/runtime.txt Signed-off-by: Yanmin Zhang <yanmin.zhang@intel.com> Signed-off-by: ShuoX Liu <shuox.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM: Move disabling/enabling runtime PM to late suspend/early resumeRafael J. Wysocki2013-01-061-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the PM core disables runtime PM for all devices right after executing subsystem/driver .suspend() callbacks for them and re-enables it right before executing subsystem/driver .resume() callbacks for them. This may lead to problems when there are two devices such that the .suspend() callback executed for one of them depends on runtime PM working for the other. In that case, if runtime PM has already been disabled for the second device, the first one's .suspend() won't work correctly (and analogously for resume). To make those issues go away, make the PM core disable runtime PM for devices right before executing subsystem/driver .suspend_late() callbacks for them and enable runtime PM for them right after executing subsystem/driver .resume_early() callbacks for them. This way the potential conflitcs between .suspend_late()/.resume_early() and their runtime PM counterparts are still prevented from happening, but the subtle ordering issues related to disabling/enabling runtime PM for devices during system suspend/resume are much easier to avoid. Reported-and-tested-by: Jan-Matthias Braun <jan_braun@gmx.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: 3.4+ <stable@vger.kernel.org>
* PM: Run the driver callback directly if the subsystem one is not thereRafael J. Wysocki2011-12-211-62/+68
| | | | | | | | | | | | | | | | | | | | | Make the PM core execute driver PM callbacks directly if the corresponding subsystem callbacks are not present. There are three reasons for doing that. First, it reflects the behavior of drivers/base/dd.c:really_probe() that runs the driver's .probe() callback directly if the bus type's one is not defined, so this change will remove one arbitrary difference between the PM core and the remaining parts of the driver core. Second, it will allow some subsystems, whose PM callbacks don't do anything except for executing driver callbacks, to be simplified quite a bit by removing those "forward-only" callbacks. Finally, it will allow us to remove one level of indirection in the system suspend and resume code paths where it is not necessary, which is going to lead to less debug noise with initcall_debug passed in the kernel command line (messages won't be printed for driverless devices whose subsystems don't provide PM callbacks among other things). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Make documentation follow the new behavior of irq_safeRafael J. Wysocki2011-11-281-5/+6
| | | | | | | | The runtime PM core code behavior related to the power.irq_safe device flag has changed recently and the documentation should be modified to reflect it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Domains: Document how PM domains are used by the PM coreRafael J. Wysocki2011-11-281-11/+18
| | | | | | | | | The current power management documentation in Documentation/power/ either doesn't cover PM domains at all, or gives inaccurate information about them, so update the relevant files in there to follow the code. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Automatically retry failed autosuspendsAlan Stern2011-11-041-0/+10
| | | | | | | | | | | | | | | | | | | | | | | Originally, the runtime PM core would send an idle notification whenever a suspend attempt failed. The idle callback routine could then schedule a delayed suspend for some time later. However this behavior was changed by commit f71648d73c1650b8b4aceb3856bebbde6daa3b86 (PM / Runtime: Remove idle notification after failing suspend). No notifications were sent, and there was no clear mechanism to retry failed suspends. This caused problems for the usbhid driver, because it fails autosuspend attempts as long as a key is being held down. Therefore this patch (as1492) adds a mechanism for retrying failed autosuspends. If the callback routine updates the last_busy field so that the next autosuspend expiration time is in the future, the autosuspend will automatically be rescheduled. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Henrik Rydberg <rydberg@euromail.se> Cc: <stable@kernel.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* Merge branch 'pm-runtime' into pm-for-linusRafael J. Wysocki2011-10-161-7/+12
|\ | | | | | | | | | | | | * pm-runtime: PM / Runtime: Handle .runtime_suspend() failure correctly PM / Runtime: Fix kerneldoc comment for rpm_suspend() PM / Runtime: Update document about callbacks
| * PM / Runtime: Update document about callbacksMing Lei2011-10-101-7/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Support for device power domains has been introduced in commit 9659cc0678b954f187290c6e8b247a673c5d37e1 (PM: Make system-wide PM and runtime PM treat subsystems consistently), also power domain callbacks will take precedence over subsystem ones from commit 4d27e9dcff00a6425d779b065ec8892e4f391661(PM: Make power domain callbacks take precedence over subsystem ones). So update part of "Device Runtime PM Callbacks" in Documentation/power/runtime_pm.txt. Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* | Merge branch 'pm-runtime' into pm-for-linusRafael J. Wysocki2011-10-071-0/+2
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | * pm-runtime: PM / Tracing: build rpm-traces.c only if CONFIG_PM_RUNTIME is set PM / Runtime: Replace dev_dbg() with trace_rpm_*() PM / Runtime: Introduce trace points for tracing rpm_* functions PM / Runtime: Don't run callbacks under lock for power.irq_safe set USB: Add wakeup info to debugging messages PM / Runtime: pm_runtime_idle() can be called in atomic context PM / Runtime: Add macro to test for runtime PM events PM / Runtime: Add might_sleep() to runtime PM functions
| * PM / Runtime: pm_runtime_idle() can be called in atomic contextMing Lei2011-09-211-0/+1
| | | | | | | | | | | | | | | | | | Add to pm_runtime_idle the list of functions that can be called in atomic context if pm_runtime_irq_safe() has been called for the device. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
| * PM / Runtime: Add might_sleep() to runtime PM functionsColin Cross2011-08-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some of the entry points to pm runtime are not safe to call in atomic context unless pm_runtime_irq_safe() has been called. Inspecting the code, it is not immediately obvious that the functions sleep at all, as they run inside a spin_lock_irqsave, but under some conditions they can drop the lock and turn on irqs. If a driver incorrectly calls the pm_runtime apis, it can cause sleeping and irq processing when it expects to stay in atomic context. Add might_sleep_if to the majority of the __pm_runtime_* entry points to enforce correct usage. Add pm_runtime_put_sync_autosuspend to the list of functions that can be called in atomic context. Signed-off-by: Colin Cross <ccross@android.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* | PM / Runtime: Correct documentation of pm_runtime_irq_safe()Rafael J. Wysocki2011-08-251-2/+1
|/ | | | | | | | | The description of pm_runtime_irq_safe() has to be updated to follow the code after commit 02b2677 (PM / Runtime: Allow _put_sync() from interrupts-disabled context). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Kevin Hilman <khilman@ti.com>
* PM / Runtime: Allow _put_sync() from interrupts-disabled contextKevin Hilman2011-08-051-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | Currently the use of pm_runtime_put_sync() is not safe from interrupts-disabled context because rpm_idle() will release the spinlock and enable interrupts for the idle callbacks. This enables interrupts during a time where interrupts were expected to be disabled, and can have strange side effects on drivers that expected interrupts to be disabled. This is not a bug since the documentation clearly states that only _put_sync_suspend() is safe in IRQ-safe mode. However, pm_runtime_put_sync() could be made safe when in IRQ-safe mode by releasing the spinlock but not re-enabling interrupts, which is what this patch aims to do. Problem was found when using some buggy drivers that set pm_runtime_irq_safe() and used _put_sync() in interrupts-disabled context. Reported-by: Colin Cross <ccross@google.com> Tested-by: Nishanth Menon <nm@ti.com> Signed-off-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Add new helper function: pm_runtime_status_suspended()Kevin Hilman2011-07-121-0/+3
| | | | | | | | | | | | This boolean function simply returns whether or not the runtime status of the device is 'suspended'. Unlike pm_runtime_suspended(), this function returns the runtime status whether or not runtime PM for the device has been disabled or not. Also add entry to Documentation/power/runtime.txt Signed-off-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Replace "run-time" with "runtime" in documentationRafael J. Wysocki2011-07-061-65/+65
| | | | | | | | The runtime PM documentation and kerneldoc comments sometimes spell "runtime" with a dash (i.e. "run-time"). Replace all of those instances with "runtime" to make the naming consistent. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Improve documentation of enable, disable and barrierRafael J. Wysocki2011-07-061-4/+14
| | | | | | | | | | | | The runtime PM documentation in Documentation/power/runtime_pm.txt doesn't say that pm_runtime_enable() and pm_runtime_disable() work by operating on power.disable_depth, which is wrong, because the possibility of nesting disables doesn't follow from the description of these functions. Also, there is no description of pm_runtime_barrier() at all in the document, which is confusing. Improve the documentation by fixing those issues. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Limit race conditions between runtime PM and system sleep (v2)Rafael J. Wysocki2011-07-061-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <rjw@sisk.pl> Acked-by: Kevin Hilman <khilman@ti.com>
* PM / Runtime: Return special error code if runtime PM is disabledRafael J. Wysocki2011-07-021-2/+4
| | | | | | | | | | | | | | | Some callers of pm_runtime_get_sync() and other runtime PM helper functions, scsi_autopm_get_host() and scsi_autopm_get_device() in particular, need to distinguish error codes returned when runtime PM is disabled (i.e. power.disable_depth is nonzero for the given device) from error codes returned in other situations. For this reason, make the runtime PM helper functions return -EACCES when power.disable_depth is nonzero and ensure that this error code won't be returned by them in any other circumstances. Modify scsi_autopm_get_host() and scsi_autopm_get_device() to check the error code returned by pm_runtime_get_sync() and ignore -EACCES. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Update documentation of interactions with system sleepRafael J. Wysocki2011-07-021-8/+19
| | | | | | | | | | | | The documents describing the interactions between runtime PM and system sleep generally refer to the model in which the system sleep state is entered through a global firmware or hardware operation. As a result, some recommendations given in there are not entirely suitable for systems in which this is not the case. Update the documentation to take the existence of those systems into account. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Kevin Hilman <khilman@ti.com>
* PM: Introduce generic "noirq" callback routines for subsystems (v2)Rafael J. Wysocki2011-07-021-2/+30
| | | | | | | | | | Introduce generic "noirq" power management callback routines for subsystems in addition to the "regular" generic PM callback routines. The new routines will be used, among other things, for implementing system-wide PM transitions support for generic PM domains. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Update documentation regarding driver removalRafael J. Wysocki2011-07-021-5/+21
| | | | | | | | | | | Commit e1866b33b1e89f077b7132daae3dfd9a594e9a1a (PM / Runtime: Rework runtime PM handling during driver removal) forgot to update the documentation in Documentation/power/runtime_pm.txt to match the new code in drivers/base/dd.c. Update that documentation to match the code it describes. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Kevin Hilman <khilman@ti.com>
* PM: Documentation: fix typo: pm_runtime_idle_sync() doesn't exist.Kevin Hilman2011-07-021-1/+1
| | | | | | | | Replace reference to pm_runtime_idle_sync() in the driver core with pm_runtime_put_sync() which is used in the code. Signed-off-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / Runtime: Update doc: usage count no longer incremented across system PMKevin Hilman2011-06-211-5/+0
| | | | | | | | | | | Commit e8665002477f0278f84f898145b1f141ba26ee26 (PM: Allow pm_runtime_suspend() to succeed during system suspend) removed usage count increment across system PM. Update doc to reflect this. Signed-off-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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