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2022-04-20PM: core: keep irq flags in device_pm_check_callbacks()Dmitry Baryshkov1-2/+4
[ Upstream commit 524bb1da785a7ae43dd413cd392b5071c6c367f8 ] The function device_pm_check_callbacks() can be called under the spin lock (in the reported case it happens from genpd_add_device() -> dev_pm_domain_set(), when the genpd uses spinlocks rather than mutexes. However this function uncoditionally uses spin_lock_irq() / spin_unlock_irq(), thus not preserving the CPU flags. Use the irqsave/irqrestore instead. The backtrace for the reference: [ 2.752010] ------------[ cut here ]------------ [ 2.756769] raw_local_irq_restore() called with IRQs enabled [ 2.762596] WARNING: CPU: 4 PID: 1 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x34/0x50 [ 2.772338] Modules linked in: [ 2.775487] CPU: 4 PID: 1 Comm: swapper/0 Tainted: G S 5.17.0-rc6-00384-ge330d0d82eff-dirty #684 [ 2.781384] Freeing initrd memory: 46024K [ 2.785839] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 2.785841] pc : warn_bogus_irq_restore+0x34/0x50 [ 2.785844] lr : warn_bogus_irq_restore+0x34/0x50 [ 2.785846] sp : ffff80000805b7d0 [ 2.785847] x29: ffff80000805b7d0 x28: 0000000000000000 x27: 0000000000000002 [ 2.785850] x26: ffffd40e80930b18 x25: ffff7ee2329192b8 x24: ffff7edfc9f60800 [ 2.785853] x23: ffffd40e80930b18 x22: ffffd40e80930d30 x21: ffff7edfc0dffa00 [ 2.785856] x20: ffff7edfc09e3768 x19: 0000000000000000 x18: ffffffffffffffff [ 2.845775] x17: 6572206f74206465 x16: 6c696166203a3030 x15: ffff80008805b4f7 [ 2.853108] x14: 0000000000000000 x13: ffffd40e809550b0 x12: 00000000000003d8 [ 2.860441] x11: 0000000000000148 x10: ffffd40e809550b0 x9 : ffffd40e809550b0 [ 2.867774] x8 : 00000000ffffefff x7 : ffffd40e809ad0b0 x6 : ffffd40e809ad0b0 [ 2.875107] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000 [ 2.882440] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff7edfc03a8000 [ 2.889774] Call trace: [ 2.892290] warn_bogus_irq_restore+0x34/0x50 [ 2.896770] _raw_spin_unlock_irqrestore+0x94/0xa0 [ 2.901690] genpd_unlock_spin+0x20/0x30 [ 2.905724] genpd_add_device+0x100/0x2d0 [ 2.909850] __genpd_dev_pm_attach+0xa8/0x23c [ 2.914329] genpd_dev_pm_attach_by_id+0xc4/0x190 [ 2.919167] genpd_dev_pm_attach_by_name+0x3c/0xd0 [ 2.924086] dev_pm_domain_attach_by_name+0x24/0x30 [ 2.929102] psci_dt_attach_cpu+0x24/0x90 [ 2.933230] psci_cpuidle_probe+0x2d4/0x46c [ 2.937534] platform_probe+0x68/0xe0 [ 2.941304] really_probe.part.0+0x9c/0x2fc [ 2.945605] __driver_probe_device+0x98/0x144 [ 2.950085] driver_probe_device+0x44/0x15c [ 2.954385] __device_attach_driver+0xb8/0x120 [ 2.958950] bus_for_each_drv+0x78/0xd0 [ 2.962896] __device_attach+0xd8/0x180 [ 2.966843] device_initial_probe+0x14/0x20 [ 2.971144] bus_probe_device+0x9c/0xa4 [ 2.975092] device_add+0x380/0x88c [ 2.978679] platform_device_add+0x114/0x234 [ 2.983067] platform_device_register_full+0x100/0x190 [ 2.988344] psci_idle_init+0x6c/0xb0 [ 2.992113] do_one_initcall+0x74/0x3a0 [ 2.996060] kernel_init_freeable+0x2fc/0x384 [ 3.000543] kernel_init+0x28/0x130 [ 3.004132] ret_from_fork+0x10/0x20 [ 3.007817] irq event stamp: 319826 [ 3.011404] hardirqs last enabled at (319825): [<ffffd40e7eda0268>] __up_console_sem+0x78/0x84 [ 3.020332] hardirqs last disabled at (319826): [<ffffd40e7fd6d9d8>] el1_dbg+0x24/0x8c [ 3.028458] softirqs last enabled at (318312): [<ffffd40e7ec90410>] _stext+0x410/0x588 [ 3.036678] softirqs last disabled at (318299): [<ffffd40e7ed1bf68>] __irq_exit_rcu+0x158/0x174 [ 3.045607] ---[ end trace 0000000000000000 ]--- Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-03PM: sleep: core: Fix the handling of pending runtime resume requestsRafael J. Wysocki1-6/+10
commit e3eb6e8fba65094328b8dca635d00de74ba75b45 upstream. It has been reported that system-wide suspend may be aborted in the absence of any wakeup events due to unforseen interactions of it with the runtume PM framework. One failing scenario is when there are multiple devices sharing an ACPI power resource and runtime-resume needs to be carried out for one of them during system-wide suspend (for example, because it needs to be reconfigured before the whole system goes to sleep). In that case, the runtime-resume of that device involves turning the ACPI power resource "on" which in turn causes runtime-resume requests to be queued up for all of the other devices sharing it. Those requests go to the runtime PM workqueue which is frozen during system-wide suspend, so they are not actually taken care of until the resume of the whole system, but the pm_runtime_barrier() call in __device_suspend() sees them and triggers system wakeup events for them which then cause the system-wide suspend to be aborted if wakeup source objects are in active use. Of course, the logic that leads to triggering those wakeup events is questionable in the first place, because clearly there are cases in which a pending runtime resume request for a device is not connected to any real wakeup events in any way (like the one above). Moreover, it is racy, because the device may be resuming already by the time the pm_runtime_barrier() runs and so if the driver doesn't take care of signaling the wakeup event as appropriate, it will be lost. However, if the driver does take care of that, the extra pm_wakeup_event() call in the core is redundant. Accordingly, drop the conditional pm_wakeup_event() call fron __device_suspend() and make the latter call pm_runtime_barrier() alone. Also modify the comment next to that call to reflect the new code and extend it to mention the need to avoid unwanted interactions between runtime PM and system-wide device suspend callbacks. Fixes: 1e2ef05bb8cf8 ("PM: Limit race conditions between runtime PM and system sleep (v2)") Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Utkarsh H Patel <utkarsh.h.patel@intel.com> Tested-by: Utkarsh H Patel <utkarsh.h.patel@intel.com> Tested-by: Pengfei Xu <pengfei.xu@intel.com> Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-15PM: core: Fix handling of devices deleted during system-wide resumeRafael J. Wysocki1-5/+37
commit 0552e05fdfea191a2cf3a0abd33574b5ef9ca818 upstream. If a device is deleted by one of its system-wide resume callbacks (for example, because it does not appear to be present or accessible any more) along with its children, the resume of the children may continue leading to use-after-free errors and other issues (potentially). Namely, if the device's children are resumed asynchronously, their resume may have been scheduled already before the device's callback runs and so the device may be deleted while dpm_wait_for_superior() is being executed for them. The memory taken up by the parent device object may be freed then while dpm_wait() is waiting for the parent's resume callback to complete, which leads to a use-after-free. Moreover, the resume of the children is really not expected to continue after they have been unregistered, so it must be terminated right away in that case. To address this problem, modify dpm_wait_for_superior() to check if the target device is still there in the system-wide PM list of devices and if so, to increment its parent's reference counter, both under dpm_list_mtx which prevents device_del() running for the child from dropping the parent's reference counter prematurely. If the device is not present in the system-wide PM list of devices any more, the resume of it cannot continue, so check that again after dpm_wait() returns, which means that the parent's callback has been completed, and pass the result of that check to the caller of dpm_wait_for_superior() to allow it to abort the device's resume if it is not there any more. Link: https://lore.kernel.org/linux-pm/1579568452-27253-1-git-send-email-chanho.min@lge.com Reported-by: Chanho Min <chanho.min@lge.com> Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-31PM / core: Propagate dev->power.wakeup_path when no callbacksUlf Hansson1-0/+4
[ Upstream commit dc351d4c5f4fe4d0f274d6d660227be0c3a03317 ] The dev->power.direct_complete flag may become set in device_prepare() in case the device don't have any PM callbacks (dev->power.no_pm_callbacks is set). This leads to a broken behaviour, when there is child having wakeup enabled and relies on its parent to be used in the wakeup path. More precisely, when the direct complete path becomes selected for the child in __device_suspend(), the propagation of the dev->power.wakeup_path becomes skipped as well. Let's address this problem, by checking if the device is a part the wakeup path or has wakeup enabled, then prevent the direct complete path from being used. Reported-by: Loic Pallardy <loic.pallardy@st.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> [ rjw: Comment cleanup ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-10-13PM / core: Clear the direct_complete flag on errorsRafael J. Wysocki1-1/+4
commit 69e445ab8b66a9f30519842ef18be555d3ee9b51 upstream. If __device_suspend() runs asynchronously (in which case the device passed to it is in dpm_suspended_list at that point) and it returns early on an error or pending wakeup, and the power.direct_complete flag has been set for the device already, the subsequent device_resume() will be confused by that and it will call pm_runtime_enable() incorrectly, as runtime PM has not been disabled for the device by __device_suspend(). To avoid that, clear power.direct_complete if __device_suspend() is not going to disable runtime PM for the device before returning. Fixes: aae4518b3124 (PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily) Reported-by: Al Cooper <alcooperx@gmail.com> Tested-by: Al Cooper <alcooperx@gmail.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Cc: 3.16+ <stable@vger.kernel.org> # 3.16+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-19PM: core: Fix device_pm_check_callbacks()Rafael J. Wysocki1-3/+6
The device_pm_check_callbacks() function doesn't check legacy ->suspend and ->resume callback pointers under the device's bus type, class and driver, so in some cases it may set the no_pm_callbacks flag for the device incorrectly and then the callbacks may be skipped during system suspend/resume, which shouldn't happen. Fixes: aa8e54b55947 (PM / sleep: Go direct_complete if driver has no callbacks) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: 4.5+ <stable@vger.kernel.org> # 4.5+
2017-07-25PM / sleep: Check pm_wakeup_pending() in __device_suspend_noirq()Rafael J. Wysocki1-0/+5
Restore the pm_wakeup_pending() check in __device_suspend_noirq() removed by commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle) as that allows the function to return earlier if there's a wakeup event pending already (so that it may spend less time on carrying out operations that will be reversed shortly anyway) and rework the main suspend-to-idle loop to take that optimization into account. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-25PM / core: Add error argument to dpm_show_time()Rafael J. Wysocki1-11/+10
Make the core device suspend/resume code also call dpm_show_time() on failures and add an error argument to this function so that the message printed by it can reflect the success or failure condition. This makes the debug messages in question look less confusing in the failing cases. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-25PM / core: Split dpm_suspend_noirq() and dpm_resume_noirq()Rafael J. Wysocki1-21/+46
Put the device interrupts disabling and enabling as well as cpuidle_pause() and cpuidle_resume() called during the "noirq" stages of system suspend into separate functions to allow the core suspend-to-idle code to be optimized (later). The only functional difference this makes is that debug facilities and diagnostic tools will not include the above operations into the "noirq" device suspend/resume duration measurements. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22PM / sleep: Do not print debug messages by defaultRafael J. Wysocki1-8/+4
Debug messages from the system suspend/hibernation infrastructure can fill up the entire kernel log buffer in some cases and anyway they are only useful for debugging. They depend on CONFIG_PM_DEBUG, but that is set as a rule as some generally useful diagnostic facilities depend on it too. For this reason, avoid printing those messages by default, but make it possible to turn them on as needed with the help of a new sysfs attribute under /sys/power/. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-03Merge branch 'acpi-pm'Rafael J. Wysocki1-5/+5
* acpi-pm: PM / core: Drop run_wake flag from struct dev_pm_info PCI / PM: Simplify device wakeup settings code PCI / PM: Drop pme_interrupt flag from struct pci_dev ACPI / PM: Consolidate device wakeup settings code ACPI / PM: Drop run_wake from struct acpi_device_wakeup_flags ACPI / sleep: EC-based wakeup from suspend-to-idle on recent systems platform: x86: intel-hid: Wake up the system from suspend-to-idle platform: x86: intel-vbtn: Wake up the system from suspend-to-idle ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle platform/x86: Add driver for ACPI INT0002 Virtual GPIO device PCI / PM: Restore PME Enable if skipping wakeup setup PM / sleep: Print timing information if debug is enabled ACPI / PM: Clean up device wakeup enable/disable code ACPI / PM: Change log level of wakeup-related message USB / PCI / PM: Allow the PCI core to do the resume cleanup ACPI / PM: Run wakeup notify handlers synchronously Conflicts: drivers/base/power/main.c
2017-06-28PM: Constify info string used in messagesKrzysztof Kozlowski1-13/+15
The 'info' string appearing in many places points to a .rodata string so it should be passes as pointer to const. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-28PM: Constify returned PM event nameKrzysztof Kozlowski1-1/+1
The pm_verb() returns a pointer to string from .rodata so it should be marked as const. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-15ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idleRafael J. Wysocki1-5/+0
The ACPI SCI (System Control Interrupt) is set up as a wakeup IRQ during suspend-to-idle transitions and, consequently, any events signaled through it wake up the system from that state. However, on some systems some of the events signaled via the ACPI SCI while suspended to idle should not cause the system to wake up. In fact, quite often they should just be discarded. Arguably, systems should not resume entirely on such events, but in order to decide which events really should cause the system to resume and which are spurious, it is necessary to resume up to the point when ACPI SCIs are actually handled and processed, which is after executing dpm_resume_noirq() in the system resume path. For this reasons, add a loop around freeze_enter() in which the platforms can process events signaled via multiplexed IRQ lines like the ACPI SCI and add suspend-to-idle hooks that can be used for this purpose to struct platform_freeze_ops. In the ACPI case, the ->wake hook is used for checking if the SCI has triggered while suspended and deferring the interrupt-induced system wakeup until the events signaled through it are actually processed sufficiently to decide whether or not the system should resume. In turn, the ->sync hook allows all of the relevant event queues to be flushed so as to prevent events from being missed due to race conditions. In addition to that, some ACPI code processing wakeup events needs to be modified to use the "hard" version of wakeup triggers, so that it will cause a system resume to happen on device-induced wakeup events even if the "soft" mechanism to prevent the system from suspending is not enabled. However, to preserve the existing behavior with respect to suspend-to-RAM, this only is done in the suspend-to-idle case and only if an SCI has occurred while suspended. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-15PM / sleep: Print timing information if debug is enabledRafael J. Wysocki1-0/+4
Avoid printing the device suspend/resume timing information if CONFIG_PM_DEBUG is not set to reduce the log noise level. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-07Revert "ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle"Rafael J. Wysocki1-0/+5
Revert commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle) as it turned out to be premature and triggered a number of different issues on various systems. That includes, but is not limited to, premature suspend-to-RAM aborts on Dell XPS 13 (9343) reported by Dominik. The issue the commit in question attempted to address is real and will need to be taken care of going forward, but evidently more work is needed for this purpose. Reported-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-05-05ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idleRafael J. Wysocki1-5/+0
The ACPI SCI (System Control Interrupt) is set up as a wakeup IRQ during suspend-to-idle transitions and, consequently, any events signaled through it wake up the system from that state. However, on some systems some of the events signaled via the ACPI SCI while suspended to idle should not cause the system to wake up. In fact, quite often they should just be discarded. Arguably, systems should not resume entirely on such events, but in order to decide which events really should cause the system to resume and which are spurious, it is necessary to resume up to the point when ACPI SCIs are actually handled and processed, which is after executing dpm_resume_noirq() in the system resume path. For this reasons, add a loop around freeze_enter() in which the platforms can process events signaled via multiplexed IRQ lines like the ACPI SCI and add suspend-to-idle hooks that can be used for this purpose to struct platform_freeze_ops. In the ACPI case, the ->wake hook is used for checking if the SCI has triggered while suspended and deferring the interrupt-induced system wakeup until the events signaled through it are actually processed sufficiently to decide whether or not the system should resume. In turn, the ->sync hook allows all of the relevant event queues to be flushed so as to prevent events from being missed due to race conditions. In addition to that, some ACPI code processing wakeup events needs to be modified to use the "hard" version of wakeup triggers, so that it will cause a system resume to happen on device-induced wakeup events even if the "soft" mechanism to prevent the system from suspending is not enabled (that also helps to catch device-induced wakeup events occurring during suspend transitions in progress). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+1
<linux/sched/debug.h> We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/debug.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-25ktime: Cleanup ktime_set() usageThomas Gleixner1-1/+1
ktime_set(S,N) was required for the timespec storage type and is still useful for situations where a Seconds and Nanoseconds part of a time value needs to be converted. For anything where the Seconds argument is 0, this is pointless and can be replaced with a simple assignment. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
2016-12-13Merge tag 'driver-core-4.10-rc1' of ↵Linus Torvalds1-6/+81
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here's the new driver core patches for 4.10-rc1. Big thing here is the nice addition of "functional dependencies" to the driver core. The idea has been talked about for a very long time, great job to Rafael for stepping up and implementing it. It's been tested for longer than the 4.9-rc1 date, we held off on merging it earlier in order to feel more comfortable about it. Other than that, it's just a handful of small other patches, some good cleanups to the mess that is the firmware class code, and we have a test driver for the deferred probe logic. All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (30 commits) firmware: Correct handling of fw_state_wait() return value driver core: Silence device links sphinx warning firmware: remove warning at documentation generation time drivers: base: dma-mapping: Fix typo in dmam_alloc_non_coherent comments driver core: test_async: fix up typo found by 0-day firmware: move fw_state_is_done() into UHM section firmware: do not use fw_lock for fw_state protection firmware: drop bit ops in favor of simple state machine firmware: refactor loading status firmware: fix usermode helper fallback loading driver core: firmware_class: convert to use class_groups driver core: devcoredump: convert to use class_groups driver core: class: add class_groups support kernfs: Declare two local data structures static driver-core: fix platform_no_drv_owner.cocci warnings drivers/base/memory.c: Remove unused 'first_page' variable driver core: add CLASS_ATTR_WO() drivers: base: cacheinfo: support DT overrides for cache properties drivers: base: cacheinfo: add pr_fmt logging drivers: base: cacheinfo: fix boot error message when acpi is enabled ...
2016-12-12Merge branches 'pm-core', 'pm-qos' and 'pm-avs'Rafael J. Wysocki1-1/+1
* pm-core: PM / core: Fix bug in the error handling of async suspend PM / wakeirq: Fix dedicated wakeirq for drivers not using autosuspend PM / Runtime: Defer resuming of the device in pm_runtime_force_resume() PM / Runtime: Don't allow to suspend a device with an active child net: smsc911x: Synchronize the runtime PM status during system suspend PM / Runtime: Convert pm_runtime_set_suspended() to return an int PM / Runtime: Clarify comment in rpm_resume() when resuming the parent PM / Runtime: Remove the exported function pm_children_suspended() * pm-qos: PM / QoS: Export dev_pm_qos_update_user_latency_tolerance PM / QoS: Fix writing 'auto' to pm_qos_latency_tolerance_us PM / QoS: Improve sysfs pm_qos_latency_tolerance validation * pm-avs: PM / AVS: rockchip-io: make the log more consistent
2016-12-08PM / core: Fix bug in the error handling of async suspendSahitya Tummala1-1/+1
If async_suspend is enabled for parent and child devices, then PM framework has to ensure that parent's async suspend gets called only after child's async suspend is done. In case if child's async suspend fails with error, then parent's async suspend must not be invoked. The current code uses async_error to ensure this but there is a problem with it in __device_suspend(). This function notifies the completion of child's async suspend before updating its error via async_error variable. As a result, parent's async suspend gets invoked even though it's child suspend has failed. Fix this bug by updating the async_error before notifying the child's completion. Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> [ rjw: Rearranged wthitespace ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-11PM / sleep: don't suspend parent when async child suspend_{noirq, late} failsBrian Norris1-4/+4
Consider two devices, A and B, where B is a child of A, and B utilizes asynchronous suspend (it does not matter whether A is sync or async). If B fails to suspend_noirq() or suspend_late(), or is interrupted by a wakeup (pm_wakeup_pending()), then it aborts and sets the async_error variable. However, device A does not (immediately) check the async_error variable; it may continue to run its own suspend_noirq()/suspend_late() callback. This is bad. We can resolve this problem by doing our error and wakeup checking (particularly, for the async_error flag) after waiting for children to suspend, instead of before. This also helps align the logic for the noirq and late suspend cases with the logic in __device_suspend(). It's easy to observe this erroneous behavior by, for example, forcing a device to sleep a bit in its suspend_noirq() (to ensure the parent is waiting for the child to complete), then return an error, and watch the parent suspend_noirq() still get called. (Or similarly, fake a wakeup event at the right (or is it wrong?) time.) Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late) Fixes: 28b6fd6e3779 (PM / sleep: Asynchronous threads for suspend_noirq) Reported-by: Jeffy Chen <jeffy.chen@rock-chips.com> Signed-off-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-10-31PM / sleep: Make async suspend/resume of devices use device linksRafael J. Wysocki1-6/+79
Make the device suspend/resume part of the core system suspend/resume code use device links to ensure that supplier and consumer devices will be suspended and resumed in the right order in case of async suspend/resume. The idea, roughly, is to use dpm_wait() to wait for all consumers before a supplier device suspend and to wait for all suppliers before a consumer device resume. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-31driver core: Functional dependencies tracking supportRafael J. Wysocki1-0/+2
Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-21PM / sleep: Handle failures in device_suspend_late() consistentlyRafael J. Wysocki1-2/+3
Grygorii Strashko reports: The PM runtime will be left disabled for the device if its .suspend_late() callback fails and async suspend is not allowed for this device. In this case device will not be added in dpm_late_early_list and dpm_resume_early() will ignore this device, as result PM runtime will be disabled for it forever (side effect: after 8 subsequent failures for the same device the PM runtime will be reenabled due to disable_depth overflow). To fix this problem, add devices to dpm_late_early_list regardless of whether or not device_suspend_late() returns errors for them. That will ensure failures in there to be handled consistently for all devices regardless of their async suspend/resume status. Reported-by: Grygorii Strashko <grygorii.strashko@ti.com> Tested-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: All applicable <stable@vger.kernel.org>
2016-04-28PM / sleep: Drop unused `info' variableThierry Reding1-13/+5
Commit 32e8d689dc12 (PM / sleep: trace_device_pm_callback coverage in dpm_prepare/complete) removed all users of this variable but forgot to remove the variable itself. Signed-off-by: Thierry Reding <treding@nvidia.com> [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-01-08PM / sleep: Go direct_complete if driver has no callbacksTomeu Vizoso1-0/+35
If a suitable prepare callback cannot be found for a given device and its driver has no PM callbacks at all, assume that it can go direct to complete when the system goes to sleep. The reason for this is that there's lots of devices in a system that do no PM at all and there's no reason for them to prevent their ancestors to do direct_complete if they can support it. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-11-30PM / sleep: prohibit devices probing during suspend/hibernationStrashko, Grygorii1-0/+17
It is unsafe [1] if probing of devices will happen during suspend or hibernation and system behavior will be unpredictable in this case. So, let's prohibit device's probing in dpm_prepare() and defer their probing instead. The normal behavior will be restored in dpm_complete(). This patch introduces new DD core APIs: device_block_probing() It will disable probing of devices and defer their probes instead. device_unblock_probing() It will restore normal behavior and trigger re-probing of deferred devices. [1] https://lkml.org/lkml/2015/9/11/554 Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-07-22PM / sleep: Allow devices without runtime PM to do direct-completeAlan Stern1-1/+1
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>
2015-06-19Merge branch 'pm-wakeirq'Rafael J. Wysocki1-0/+3
* pm-wakeirq: PM / wakeirq: Fix typo in prototype for dev_pm_set_dedicated_wake_irq PM / Wakeirq: Add automated device wake IRQ handling
2015-06-10PM / sleep: trace_device_pm_callback coverage in dpm_prepare/completeTodd E Brandt1-6/+5
Move the trace_device_pm_callback locations for dpm_prepare and dpm_complete to encompass the attempt to capture the device mutex prior to callback. This is needed by analyze_suspend to identify gaps in the trace output caused by the delay in locking the mutex for a device. Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-05-20PM / Wakeirq: Add automated device wake IRQ handlingTony Lindgren1-0/+3
Turns out we can automate the handling for the device_may_wakeup() quite a bit by using the kernel wakeup source list as suggested by Rafael J. Wysocki <rjw@rjwysocki.net>. And as some hardware has separate dedicated wake-up interrupt in addition to the IO interrupt, we can automate the handling by adding a generic threaded interrupt handler that just calls the device PM runtime to wake up the device. This allows dropping code from device drivers as we currently are doing it in multiple ways, and often wrong. For most drivers, we should be able to drop the following boilerplate code from runtime_suspend and runtime_resume functions: ... device_init_wakeup(dev, true); ... if (device_may_wakeup(dev)) enable_irq_wake(irq); ... if (device_may_wakeup(dev)) disable_irq_wake(irq); ... device_init_wakeup(dev, false); ... We can replace it with just the following init and exit time code: ... device_init_wakeup(dev, true); dev_pm_set_wake_irq(dev, irq); ... dev_pm_clear_wake_irq(dev); device_init_wakeup(dev, false); ... And for hardware with dedicated wake-up interrupts: ... device_init_wakeup(dev, true); dev_pm_set_dedicated_wake_irq(dev, irq); ... dev_pm_clear_wake_irq(dev); device_init_wakeup(dev, false); ... Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-03-18PM / sleep: add pm-trace support for suspending phaseZhonghui Fu1-4/+16
Occasionally, the system can't come back up after suspend/resume due to problems of device suspending phase. This patch make PM_TRACE infrastructure cover device suspending phase of suspend/resume process, and the information in RTC can tell developers which device suspending function make system hang. Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-10-27PM / Sleep: fix async suspend_late/freeze_late error handlingImre Deak1-0/+2
If an asynchronous suspend_late or freeze_late callback fails during the SUSPEND, FREEZE or QUIESCE phases, we don't propagate the corresponding error correctly, in effect ignoring the error and continuing the suspend-to-ram/hibernation. During suspend-to-ram this could leave some devices without a valid saved context, leading to a failure to reinitialize them during resume. During hibernation this could leave some devices active interfeering with the creation / restoration of the hibernation image. Also this could leave the corresponding devices without a valid saved context and failure to reinitialize them during resume. Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late) Signed-off-by: Imre Deak <imre.deak@intel.com> Cc: 3.15+ <stable@vger.kernel.org> # 3.15+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-09-30PM / sleep: Export dpm_suspend_late/noirq() and dpm_resume_early/noirq()Rafael J. Wysocki1-4/+4
Subsequent change sets will add platform-related operations between dpm_suspend_late() and dpm_suspend_noirq() as well as between dpm_resume_noirq() and dpm_resume_early() in suspend_enter(), so export these functions for suspend_enter() to be able to call them separately and split the invocations of dpm_suspend_end() and dpm_resume_start() in there accordingly. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-07-29PM / sleep: fix kernel-doc warnings in drivers/base/power/main.cRandy Dunlap1-0/+5
Fix kernel-doc warnings in drivers/base/power/main.c: Warning(..//drivers/base/power/main.c:473): No description found for parameter 'async' Warning(..//drivers/base/power/main.c:601): No description found for parameter 'async' Warning(..//drivers/base/power/main.c:1012): No description found for parameter 'async' Warning(..//drivers/base/power/main.c:1151): No description found for parameter 'async' Warning(..//drivers/base/power/main.c:1305): No description found for parameter 'info' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-11PM / sleep: trace events for device PM callbacksTodd E Brandt1-4/+10
Adds two trace events which supply the same info that initcall_debug provides, but via ftrace instead of dmesg. The existing initcall_debug calls require the pm_print_times_enabled var to be set (either via sysfs or via the kernel cmd line). The new trace events provide all the same info as the initcall_debug prints but with less overhead, and also with coverage of device prepare and complete device callbacks. These events replace the device_pm_report_time event (which has been removed). device_pm_callback_start is called first and provides the device and callback info. device_pm_callback_end is called after with the device name and error info. The time and pid are gathered from the trace data headers. Signed-off-by: Todd Brandt <todd.e.brandt@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-07PM / sleep: trace events for suspend/resumeTodd E Brandt1-0/+16
Adds trace events that give finer resolution into suspend/resume. These events are graphed in the timelines generated by the analyze_suspend.py script. They represent large areas of time consumed that are typical to suspend and resume. The event is triggered by calling the function "trace_suspend_resume" with three arguments: a string (the name of the event to be displayed in the timeline), an integer (case specific number, such as the power state or cpu number), and a boolean (where true is used to denote the start of the timeline event, and false to denote the end). The suspend_resume trace event reproduces the data that the machine_suspend trace event did, so the latter has been removed. Signed-off-by: Todd Brandt <todd.e.brandt@intel.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-17PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarilyRafael J. Wysocki1-15/+51
Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to resume all runtime-suspended devices during system suspend, mostly because those devices may need to be reprogrammed due to different wakeup settings for system sleep and for runtime PM. For some devices, though, it's OK to remain in runtime suspend throughout a complete system suspend/resume cycle (if the device was in runtime suspend at the start of the cycle). We would like to do this whenever possible, to avoid the overhead of extra power-up and power-down events. However, problems may arise because the device's descendants may require it to be at full power at various points during the cycle. Therefore the most straightforward way to do this safely is if the device and all its descendants can remain runtime suspended until the complete stage of system resume. To this end, introduce a new device PM flag, power.direct_complete and modify the PM core to use that flag as follows. If the ->prepare() callback of a device returns a positive number, the PM core will regard that as an indication that it may leave the device runtime-suspended. It will then check if the system power transition in progress is a suspend (and not hibernation in particular) and if the device is, indeed, runtime-suspended. In that case, the PM core will set the device's power.direct_complete flag. Otherwise it will clear power.direct_complete for the device and it also will later clear it for the device's parent (if there's one). Next, the PM core will not invoke the ->suspend() ->suspend_late(), ->suspend_irq(), ->resume_irq(), ->resume_early(), or ->resume() callbacks for all devices having power.direct_complete set. It will invoke their ->complete() callbacks, however, and those callbacks are then responsible for resuming the devices as appropriate, if necessary. For example, in some cases they may need to queue up runtime resume requests for the devices using pm_request_resume(). Changelog partly based on an Alan Stern's description of the idea (http://marc.info/?l=linux-pm&m=139940466625569&w=2). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu>
2014-03-20Merge branch 'pm-cpufreq'Rafael J. Wysocki1-0/+5
* pm-cpufreq: (30 commits) intel_pstate: Set core to min P state during core offline cpufreq: Add stop CPU callback to cpufreq_driver interface cpufreq: Remove unnecessary braces cpufreq: Fix checkpatch errors and warnings cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs cpufreq: remove unused notifier: CPUFREQ_{SUSPENDCHANGE|RESUMECHANGE} cpufreq: Do not allow ->setpolicy drivers to provide ->target cpufreq: arm_big_little: set 'physical_cluster' for each CPU cpufreq: arm_big_little: make vexpress driver depend on bL core driver cpufreq: SPEAr: Instantiate as platform_driver cpufreq: Remove unnecessary variable/parameter 'frozen' cpufreq: Remove cpufreq_generic_exit() cpufreq: add 'freq_table' in struct cpufreq_policy cpufreq: Reformat printk() statements cpufreq: Tegra: Use cpufreq_generic_suspend() cpufreq: s5pv210: Use cpufreq_generic_suspend() cpufreq: exynos: Use cpufreq_generic_suspend() cpufreq: Implement cpufreq_generic_suspend() cpufreq: suspend governors on system suspend/hibernate cpufreq: move call to __find_governor() to cpufreq_init_policy() ...
2014-03-06cpufreq: suspend governors on system suspend/hibernateViresh Kumar1-0/+5
This patch adds cpufreq suspend/resume calls to dpm_{suspend|resume}() for handling suspend/resume of cpufreq governors. Lan Tianyu (Intel) & Jinhyuk Choi (Broadcom) found an issue where the tunables configuration for clusters/sockets with non-boot CPUs was lost after system suspend/resume, as we were notifying governors with CPUFREQ_GOV_POLICY_EXIT on removal of the last CPU for that policy which caused the tunables memory to be freed. This is fixed by preventing any governor operations from being carried out between the device suspend and device resume stages of system suspend and resume, respectively. We could have added these callbacks at dpm_{suspend|resume}_noirq() level, but there is an additional problem that the majority of I/O devices is already suspended at that point and if cpufreq drivers want to change the frequency before suspending, then that not be possible on some platforms (which depend on peripherals like i2c, regulators, etc). Reported-and-tested-by: Lan Tianyu <tianyu.lan@intel.com> Reported-by: Jinhyuk Choi <jinchoi@broadcom.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [rjw: Changelog] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-20PM / sleep: Asynchronous threads for suspend_lateLiu, Chuansheng1-12/+54
In analogy with commits 5af84b82701a and 97df8c12995, using asynchronous threads can improve the overall suspend_late time significantly. This patch is for suspend_late phase. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-20PM / sleep: Asynchronous threads for suspend_noirqLiu, Chuansheng1-11/+57
In analogy with commits 5af84b82701a and 97df8c12995, using asynchronous threads can improve the overall suspend_noirq time significantly. This patch is for suspend_noirq phase. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-20PM / sleep: Asynchronous threads for resume_earlyLiu, Chuansheng1-11/+44
In analogy with commits 5af84b82701a and 97df8c12995, using asynchronous threads can improve the overall resume_early time significantly. This patch is for resume_early phase. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-20PM / sleep: Asynchronous threads for resume_noirqLiu, Chuansheng1-16/+50
In analogy with commits 5af84b82701a and 97df8c12995, using asynchronous threads can improve the overall resume_noirq time significantly. One typical case is: In resume_noirq phase and for the PCI devices, the function pci_pm_resume_noirq() will be called, and there is one d3_delay (10ms) at least. With the way of asynchronous threads, we just need wait d3_delay time once in parallel for each calling, which saves much time to resume quickly. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-20PM / sleep: Two flags for async suspend_noirq and suspend_lateLiu, Chuansheng1-2/+22
The patch is a helper adding two new flags for implementing async threads for suspend_noirq and suspend_late. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-08Revert "cpufreq: suspend governors on system suspend/hibernate"Rafael J. Wysocki1-3/+0
Commit 5a87182aa21d (cpufreq: suspend governors on system suspend/hibernate) causes hibernation problems to happen on Bjørn Mork's and Paul Bolle's systems, so revert it. Fixes: 5a87182aa21d (cpufreq: suspend governors on system suspend/hibernate) Reported-by: Bjørn Mork <bjorn@mork.no> Reported-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-06Merge branches 'pm-cpuidle' and 'pm-cpufreq'Rafael J. Wysocki1-0/+3
* pm-cpuidle: cpuidle: Check for dev before deregistering it. intel_idle: Fixed C6 state on Avoton/Rangeley processors * pm-cpufreq: cpufreq: fix garbage kobjects on errors during suspend/resume cpufreq: suspend governors on system suspend/hibernate
2013-11-28cpufreq: suspend governors on system suspend/hibernateViresh Kumar1-0/+3
This patch adds cpufreq suspend/resume calls to dpm_{suspend|resume}_noirq() for handling suspend/resume of cpufreq governors. Lan Tianyu (Intel) & Jinhyuk Choi (Broadcom) found anr issue where tunables configuration for clusters/sockets with non-boot CPUs was getting lost after suspend/resume, as we were notifying governors with CPUFREQ_GOV_POLICY_EXIT on removal of the last cpu for that policy and so deallocating memory for tunables. This is fixed by this patch as we don't allow any operation on governors after device suspend and before device resume now. Reported-and-tested-by: Lan Tianyu <tianyu.lan@intel.com> Reported-by: Jinhyuk Choi <jinchoi@broadcom.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [rjw: Changelog, minor cleanups] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>