linux/drivers/base/power/runtime.c, branch v3.7-rc2

PM / Runtime: let rpm_resume() succeed if RPM_ACTIVE, even when disabled, v2

2012-09-22T19:15:08Z

There are several drivers where the return value of pm_runtime_get_sync() is used to decide whether or not it is safe to access hardware and that don't provide .suspend() callbacks for system suspend (but may use late/noirq callbacks.) If such a driver happens to call pm_runtime_get_sync() during system suspend, after the core has disabled runtime PM, it will get the error code and will decide that the hardware should not be accessed, although this may be a wrong conclusion, depending on the state of the device when runtime PM was disabled. Drivers might work around this problem by using a test like: ret = pm_runtime_get_sync(dev); if (!ret || (ret == -EACCES && driver_private_data(dev)->suspended)) { /* access hardware */ } where driver_private_data(dev)->suspended is a flag set by the driver's .suspend() method (that would have to be added for this purpose). However, that potentially would need to be done by multiple drivers which means quite a lot of duplicated code and bloat. To avoid that we can use the observation that the core sets dev->power.is_suspended before disabling runtime PM and use that instead of the driver's private flag. Still, potentially many drivers would need to repeat that same check in quite a few places, so it's better to let the core do it. Then we can be a bit smarter and check whether or not runtime PM was disabled by the core only (disable_depth == 1) or by someone else in addition to the core (disable_depth > 1). In the former case rpm_resume() can return 1 if the runtime PM status is RPM_ACTIVE, because it means the device was active when the core disabled runtime PM. In the latter case it should still return -EACCES, because it isn't clear why runtime PM has been disabled. Tested on AM3730/Beagle-xM where a wakeup IRQ firing during the late suspend phase triggers runtime PM activity in the I2C driver since the wakeup IRQ is on an I2C-connected PMIC. [rjw: Modified whitespace to follow the file's convention.] Signed-off-by: Kevin Hilman Signed-off-by: Rafael J. Wysocki

PM / Runtime: Check device PM QoS setting before "no callbacks" check

2012-08-17T17:36:36Z

If __dev_pm_qos_read_value(dev) returns a negative value, rpm_suspend() should return -EPERM for dev even if its power.no_callbacks flag is set. For this to happen, the device's power.no_callbacks flag has to be checked after the PM QoS check, so move the PM QoS check to rpm_check_suspend_allowed() (this will make it cover idle notifications as well as runtime suspend too). Signed-off-by: Rafael J. Wysocki Acked-by: Alan Stern Cc: stable@vger.kernel.org

PM / Runtime: Clear power.deferred_resume on success in rpm_suspend()

2012-08-17T17:36:36Z

The power.deferred_resume can only be set if the runtime PM status of device is RPM_SUSPENDING and it should be cleared after its status has been changed, regardless of whether or not the runtime suspend has been successful. However, it only is cleared on suspend failure, while it may remain set on successful suspend and is happily leaked to rpm_resume() executed in that case. That shouldn't happen, so if power.deferred_resume is set in rpm_suspend() after the status has been changed to RPM_SUSPENDED, clear it before calling rpm_resume(). Then, it doesn't need to be cleared before changing the status to RPM_SUSPENDING any more, because it's always cleared after the status has been changed to either RPM_SUSPENDED (on success) or RPM_ACTIVE (on failure). Signed-off-by: Rafael J. Wysocki Acked-by: Alan Stern Cc: stable@vger.kernel.org

PM / Runtime: Fix rpm_resume() return value for power.no_callbacks set

2012-08-17T17:36:35Z

For devices whose power.no_callbacks flag is set, rpm_resume() should return 1 if the device's parent is already active, so that the callers of pm_runtime_get() don't think that they have to wait for the device to resume (asynchronously) in that case (the core won't queue up an asynchronous resume in that case, so there's nothing to wait for anyway). Modify the code accordingly (and make sure that an idle notification will be queued up on success, even if 1 is to be returned). Signed-off-by: Rafael J. Wysocki Acked-by: Alan Stern Cc: stable@vger.kernel.org

PM / Runtime: Remove device fields related to suspend time, v2

2012-05-01T19:28:38Z

After the previous changes in default_stop_ok() and default_power_down_ok() for PM domains, there are two fields in struct dev_pm_info that aren't necessary any more, suspend_time and max_time_suspended_ns. Remove those fields along with all of the code that accesses them, which simplifies the runtime PM framework quite a bit. Signed-off-by: Rafael J. Wysocki

PM / Runtime: don't forget to wake up waitqueue on failure

2012-03-26T20:46:52Z

This patch (as1535) fixes a bug in the runtime PM core. When a runtime suspend attempt completes, whether successfully or not, the device's power.wait_queue is supposed to be signalled. But this doesn't happen in the failure pathway of rpm_suspend() when another autosuspend attempt is rescheduled. As a result, a task can get stuck indefinitely on the wait queue (I have seen this happen in testing). The patch fixes the problem by moving the wake_up_all() call up near the start of the failure code. Signed-off-by: Alan Stern CC: Signed-off-by: Rafael J. Wysocki

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

2011-12-25T22:43:05Z

* pm-runtime: PM / Runtime: Use device PM QoS constraints (v2)

PM: Run the driver callback directly if the subsystem one is not there

2011-12-21T21:01:05Z

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

PM / Runtime: Use device PM QoS constraints (v2)

2011-12-01T20:46:42Z

Make the runtime PM core use device PM QoS constraints to check if it is allowed to suspend a given device, so that an error code is returned if the device's own PM QoS constraint is negative or one of its children has already been suspended for too long. If this is not the case, the maximum estimated time the device is allowed to be suspended, computed as the minimum of the device's PM QoS constraint and the PM QoS constraints of its children (reduced by the difference between the current time and their suspend times) is stored in a new device's PM field power.max_time_suspended_ns that can be used by the device's subsystem or PM domain to decide whether or not to put the device into lower-power (and presumably higher-latency) states later (if the constraint is 0, which means "no constraint", the power.max_time_suspended_ns is set to -1). Additionally, the time of execution of the subsystem-level .runtime_suspend() callback for the device is recorded in the new power.suspend_time field for later use by the device's subsystem or PM domain along with power.max_time_suspended_ns (it also is used by the core code when the device's parent is suspended). Introduce a new helper function, pm_runtime_update_max_time_suspended(), allowing subsystems and PM domains (or device drivers) to update the power.max_time_suspended_ns field, for example after changing the power state of a suspended device. Signed-off-by: Rafael J. Wysocki

Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2011-11-07T03:44:47Z

* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits) Revert "tracing: Include module.h in define_trace.h" irq: don't put module.h into irq.h for tracking irqgen modules. bluetooth: macroize two small inlines to avoid module.h ip_vs.h: fix implicit use of module_get/module_put from module.h nf_conntrack.h: fix up fallout from implicit moduleparam.h presence include: replace linux/module.h with "struct module" wherever possible include: convert various register fcns to macros to avoid include chaining crypto.h: remove unused crypto_tfm_alg_modname() inline uwb.h: fix implicit use of asm/page.h for PAGE_SIZE pm_runtime.h: explicitly requires notifier.h linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h miscdevice.h: fix up implicit use of lists and types stop_machine.h: fix implicit use of smp.h for smp_processor_id of: fix implicit use of errno.h in include/linux/of.h of_platform.h: delete needless include acpi: remove module.h include from platform/aclinux.h miscdevice.h: delete unnecessary inclusion of module.h device_cgroup.h: delete needless include net: sch_generic remove redundant use of net: inet_timewait_sock doesnt need ... Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in - drivers/media/dvb/frontends/dibx000_common.c - drivers/media/video/{mt9m111.c,ov6650.c} - drivers/mfd/ab3550-core.c - include/linux/dmaengine.h