diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 3 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/suspend-flows.rst | 270 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/system-wide.rst | 1 | ||||
| -rw-r--r-- | drivers/acpi/sleep.c | 4 | ||||
| -rw-r--r-- | drivers/acpi/sleep.h | 1 | ||||
| -rw-r--r-- | drivers/acpi/wakeup.c | 81 | ||||
| -rw-r--r-- | drivers/base/power/main.c | 7 | ||||
| -rw-r--r-- | drivers/cpufreq/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/cpufreq/Kconfig.x86 | 2 | ||||
| -rw-r--r-- | drivers/platform/x86/intel_int0002_vgpio.c | 10 | ||||
| -rw-r--r-- | include/linux/acpi.h | 5 | ||||
| -rw-r--r-- | kernel/power/hibernate.c | 2 | ||||
| -rw-r--r-- | kernel/power/main.c | 7 |
13 files changed, 389 insertions, 8 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 4d5a4fe22703..c78b463f5f79 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3720,6 +3720,9 @@ Override pmtimer IOPort with a hex value. e.g. pmtmr=0x508 + pm_debug_messages [SUSPEND,KNL] + Enable suspend/resume debug messages during boot up. + pnp.debug=1 [PNP] Enable PNP debug messages (depends on the CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time diff --git a/Documentation/admin-guide/pm/suspend-flows.rst b/Documentation/admin-guide/pm/suspend-flows.rst new file mode 100644 index 000000000000..c479d7462647 --- /dev/null +++ b/Documentation/admin-guide/pm/suspend-flows.rst @@ -0,0 +1,270 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +========================= +System Suspend Code Flows +========================= + +:Copyright: |copy| 2020 Intel Corporation + +:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> + +At least one global system-wide transition needs to be carried out for the +system to get from the working state into one of the supported +:doc:`sleep states <sleep-states>`. Hibernation requires more than one +transition to occur for this purpose, but the other sleep states, commonly +referred to as *system-wide suspend* (or simply *system suspend*) states, need +only one. + +For those sleep states, the transition from the working state of the system into +the target sleep state is referred to as *system suspend* too (in the majority +of cases, whether this means a transition or a sleep state of the system should +be clear from the context) and the transition back from the sleep state into the +working state is referred to as *system resume*. + +The kernel code flows associated with the suspend and resume transitions for +different sleep states of the system are quite similar, but there are some +significant differences between the :ref:`suspend-to-idle <s2idle>` code flows +and the code flows related to the :ref:`suspend-to-RAM <s2ram>` and +:ref:`standby <standby>` sleep states. + +The :ref:`suspend-to-RAM <s2ram>` and :ref:`standby <standby>` sleep states +cannot be implemented without platform support and the difference between them +boils down to the platform-specific actions carried out by the suspend and +resume hooks that need to be provided by the platform driver to make them +available. Apart from that, the suspend and resume code flows for these sleep +states are mostly identical, so they both together will be referred to as +*platform-dependent suspend* states in what follows. + + +.. _s2idle_suspend: + +Suspend-to-idle Suspend Code Flow +================================= + +The following steps are taken in order to transition the system from the working +state to the :ref:`suspend-to-idle <s2idle>` sleep state: + + 1. Invoking system-wide suspend notifiers. + + Kernel subsystems can register callbacks to be invoked when the suspend + transition is about to occur and when the resume transition has finished. + + That allows them to prepare for the change of the system state and to clean + up after getting back to the working state. + + 2. Freezing tasks. + + Tasks are frozen primarily in order to avoid unchecked hardware accesses + from user space through MMIO regions or I/O registers exposed directly to + it and to prevent user space from entering the kernel while the next step + of the transition is in progress (which might have been problematic for + various reasons). + + All user space tasks are intercepted as though they were sent a signal and + put into uninterruptible sleep until the end of the subsequent system resume + transition. + + The kernel threads that choose to be frozen during system suspend for + specific reasons are frozen subsequently, but they are not intercepted. + Instead, they are expected to periodically check whether or not they need + to be frozen and to put themselves into uninterruptible sleep if so. [Note, + however, that kernel threads can use locking and other concurrency controls + available in kernel space to synchronize themselves with system suspend and + resume, which can be much more precise than the freezing, so the latter is + not a recommended option for kernel threads.] + + 3. Suspending devices and reconfiguring IRQs. + + Devices are suspended in four phases called *prepare*, *suspend*, + *late suspend* and *noirq suspend* (see :ref:`driverapi_pm_devices` for more + information on what exactly happens in each phase). + + Every device is visited in each phase, but typically it is not physically + accessed in more than two of them. + + The runtime PM API is disabled for every device during the *late* suspend + phase and high-level ("action") interrupt handlers are prevented from being + invoked before the *noirq* suspend phase. + + Interrupts are still handled after that, but they are only acknowledged to + interrupt controllers without performing any device-specific actions that + would be triggered in the working state of the system (those actions are + deferred till the subsequent system resume transition as described + `below <s2idle_resume_>`_). + + IRQs associated with system wakeup devices are "armed" so that the resume + transition of the system is started when one of them signals an event. + + 4. Freezing the scheduler tick and suspending timekeeping. + + When all devices have been suspended, CPUs enter the idle loop and are put + into the deepest available idle state. While doing that, each of them + "freezes" its own scheduler tick so that the timer events associated with + the tick do not occur until the CPU is woken up by another interrupt source. + + The last CPU to enter the idle state also stops the timekeeping which + (among other things) prevents high resolution timers from triggering going + forward until the first CPU that is woken up restarts the timekeeping. + That allows the CPUs to stay in the deep idle state relatively long in one + go. + + From this point on, the CPUs can only be woken up by non-timer hardware + interrupts. If that happens, they go back to the idle state unless the + interrupt that woke up one of them comes from an IRQ that has been armed for + system wakeup, in which case the system resume transition is started. + + +.. _s2idle_resume: + +Suspend-to-idle Resume Code Flow +================================ + +The following steps are taken in order to transition the system from the +:ref:`suspend-to-idle <s2idle>` sleep state into the working state: + + 1. Resuming timekeeping and unfreezing the scheduler tick. + + When one of the CPUs is woken up (by a non-timer hardware interrupt), it + leaves the idle state entered in the last step of the preceding suspend + transition, restarts the timekeeping (unless it has been restarted already + by another CPU that woke up earlier) and the scheduler tick on that CPU is + unfrozen. + + If the interrupt that has woken up the CPU was armed for system wakeup, + the system resume transition begins. + + 2. Resuming devices and restoring the working-state configuration of IRQs. + + Devices are resumed in four phases called *noirq resume*, *early resume*, + *resume* and *complete* (see :ref:`driverapi_pm_devices` for more + information on what exactly happens in each phase). + + Every device is visited in each phase, but typically it is not physically + accessed in more than two of them. + + The working-state configuration of IRQs is restored after the *noirq* resume + phase and the runtime PM API is re-enabled for every device whose driver + supports it during the *early* resume phase. + + 3. Thawing tasks. + + Tasks frozen in step 2 of the preceding `suspend <s2idle_suspend_>`_ + transition are "thawed", which means that they are woken up from the + uninterruptible sleep that they went into at that time and user space tasks + are allowed to exit the kernel. + + 4. Invoking system-wide resume notifiers. + + This is analogous to step 1 of the `suspend <s2idle_suspend_>`_ transition + and the same set of callbacks is invoked at this point, but a different + "notification type" parameter value is passed to them. + + +Platform-dependent Suspend Code Flow +==================================== + +The following steps are taken in order to transition the system from the working +state to platform-dependent suspend state: + + 1. Invoking system-wide suspend notifiers. + + This step is the same as step 1 of the suspend-to-idle suspend transition + described `above <s2idle_suspend_>`_. + + 2. Freezing tasks. + + This step is the same as step 2 of the suspend-to-idle suspend transition + described `above <s2idle_suspend_>`_. + + 3. Suspending devices and reconfiguring IRQs. + + This step is analogous to step 3 of the suspend-to-idle suspend transition + described `above <s2idle_suspend_>`_, but the arming of IRQs for system + wakeup generally does not have any effect on the platform. + + There are platforms that can go into a very deep low-power state internally + when all CPUs in them are in sufficiently deep idle states and all I/O + devices have been put into low-power states. On those platforms, + suspend-to-idle can reduce system power very effectively. + + On the other platforms, however, low-level components (like interrupt + controllers) need to be turned off in a platform-specific way (implemented + in the hooks provided by the platform driver) to achieve comparable power + reduction. + + That usually prevents in-band hardware interrupts from waking up the system, + which must be done in a special platform-dependent way. Then, the + configuration of system wakeup sources usually starts when system wakeup + devices are suspended and is finalized by the platform suspend hooks later + on. + + 4. Disabling non-boot CPUs. + + On some platforms the suspend hooks mentioned above must run in a one-CPU + configuration of the system (in particular, the hardware cannot be accessed + by any code running in parallel with the platform suspend hooks that may, + and often do, trap into the platform firmware in order to finalize the + suspend transition). + + For this reason, the CPU offline/online (CPU hotplug) framework is used + to take all of the CPUs in the system, except for one (the boot CPU), + offline (typically, the CPUs that have been taken offline go into deep idle + states). + + This means that all tasks are migrated away from those CPUs and all IRQs are + rerouted to the only CPU that remains online. + + 5. Suspending core system components. + + This prepares the core system components for (possibly) losing power going + forward and suspends the timekeeping. + + 6. Platform-specific power removal. + + This is expected to remove power from all of the system components except + for the memory controller and RAM (in order to preserve the contents of the + latter) and some devices designated for system wakeup. + + In many cases control is passed to the platform firmware which is expected + to finalize the suspend transition as needed. + + +Platform-dependent Resume Code Flow +=================================== + +The following steps are taken in order to transition the system from a +platform-dependent suspend state into the working state: + + 1. Platform-specific system wakeup. + + The platform is woken up by a signal from one of the designated system + wakeup devices (which need not be an in-band hardware interrupt) and + control is passed back to the kernel (the working configuration of the + platform may need to be restored by the platform firmware before the + kernel gets control again). + + 2. Resuming core system components. + + The suspend-time configuration of the core system components is restored and + the timekeeping is resumed. + + 3. Re-enabling non-boot CPUs. + + The CPUs disabled in step 4 of the preceding suspend transition are taken + back online and their suspend-time configuration is restored. + + 4. Resuming devices and restoring the working-state configuration of IRQs. + + This step is the same as step 2 of the suspend-to-idle suspend transition + described `above <s2idle_resume_>`_. + + 5. Thawing tasks. + + This step is the same as step 3 of the suspend-to-idle suspend transition + described `above <s2idle_resume_>`_. + + 6. Invoking system-wide resume notifiers. + + This step is the same as step 4 of the suspend-to-idle suspend transition + described `above <s2idle_resume_>`_. diff --git a/Documentation/admin-guide/pm/system-wide.rst b/Documentation/admin-guide/pm/system-wide.rst index 2b1f987b34f0..1a1924d71006 100644 --- a/Documentation/admin-guide/pm/system-wide.rst +++ b/Documentation/admin-guide/pm/system-wide.rst @@ -8,3 +8,4 @@ System-Wide Power Management :maxdepth: 2 sleep-states + suspend-flows diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c index bb1ae400ec1f..4edc8a3ce40f 100644 --- a/drivers/acpi/sleep.c +++ b/drivers/acpi/sleep.c @@ -1009,6 +1009,10 @@ static bool acpi_s2idle_wake(void) if (acpi_any_fixed_event_status_set()) return true; + /* Check wakeups from drivers sharing the SCI. */ + if (acpi_check_wakeup_handlers()) + return true; + /* * If the status bit is set for any enabled GPE other than the * EC one, the wakeup is regarded as a genuine one. diff --git a/drivers/acpi/sleep.h b/drivers/acpi/sleep.h index 41675d24a9bc..3d90480ce1b1 100644 --- a/drivers/acpi/sleep.h +++ b/drivers/acpi/sleep.h @@ -2,6 +2,7 @@ extern void acpi_enable_wakeup_devices(u8 sleep_state); extern void acpi_disable_wakeup_devices(u8 sleep_state); +extern bool acpi_check_wakeup_handlers(void); extern struct list_head acpi_wakeup_device_list; extern struct mutex acpi_device_lock; diff --git a/drivers/acpi/wakeup.c b/drivers/acpi/wakeup.c index c28244df56a5..0b2e42530adf 100644 --- a/drivers/acpi/wakeup.c +++ b/drivers/acpi/wakeup.c @@ -12,6 +12,15 @@ #include "internal.h" #include "sleep.h" +struct acpi_wakeup_handler { + struct list_head list_node; + bool (*wakeup)(void *context); + void *context; +}; + +static LIST_HEAD(acpi_wakeup_handler_head); +static DEFINE_MUTEX(acpi_wakeup_handler_mutex); + /* * We didn't lock acpi_device_lock in the file, because it invokes oops in * suspend/resume and isn't really required as this is called in S-state. At @@ -90,3 +99,75 @@ int __init acpi_wakeup_device_init(void) mutex_unlock(&acpi_device_lock); return 0; } + +/** + * acpi_register_wakeup_handler - Register wakeup handler + * @wake_irq: The IRQ through which the device may receive wakeups + * @wakeup: Wakeup-handler to call when the SCI has triggered a wakeup + * @context: Context to pass to the handler when calling it + * + * Drivers which may share an IRQ with the SCI can use this to register + * a handler which returns true when the device they are managing wants + * to trigger a wakeup. + */ +int acpi_register_wakeup_handler(int wake_irq, bool (*wakeup)(void *context), + void *context) +{ + struct acpi_wakeup_handler *handler; + + /* + * If the device is not sharing its IRQ with the SCI, there is no + * need to register the handler. + */ + if (!acpi_sci_irq_valid() || wake_irq != acpi_sci_irq) + return 0; + + handler = kmalloc(sizeof(*handler), GFP_KERNEL); + if (!handler) + return -ENOMEM; + + handler->wakeup = wakeup; + handler->context = context; + + mutex_lock(&acpi_wakeup_handler_mutex); + list_add(&handler->list_node, &acpi_wakeup_handler_head); + mutex_unlock(&acpi_wakeup_handler_mutex); + + return 0; +} +EXPORT_SYMBOL_GPL(acpi_register_wakeup_handler); + +/** + * acpi_unregister_wakeup_handler - Unregister wakeup handler + * @wakeup: Wakeup-handler passed to acpi_register_wakeup_handler() + * @context: Context passed to acpi_register_wakeup_handler() + */ +void acpi_unregister_wakeup_handler(bool (*wakeup)(void *context), + void *context) +{ + struct acpi_wakeup_handler *handler; + + mutex_lock(&acpi_wakeup_handler_mutex); + list_for_each_entry(handler, &acpi_wakeup_handler_head, list_node) { + if (handler->wakeup == wakeup && handler->context == context) { + list_del(&handler->list_node); + kfree(handler); + break; + } + } + mutex_unlock(&acpi_wakeup_handler_mutex); +} +EXPORT_SYMBOL_GPL(acpi_unregister_wakeup_handler); + +bool acpi_check_wakeup_handlers(void) +{ + struct acpi_wakeup_handler *handler; + + /* No need to lock, nothing else is running when we're called. */ + list_for_each_entry(handler, &acpi_wakeup_handler_head, list_node) { + if (handler->wakeup(handler->context)) + return true; + } + + return false; +} diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 6d1dee7051eb..fdd508a78ffd 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1922,10 +1922,6 @@ static int device_prepare(struct device *dev, pm_message_t state) if (dev->power.syscore) return 0; - WARN_ON(!pm_runtime_enabled(dev) && - dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND | - DPM_FLAG_LEAVE_SUSPENDED)); - /* * If a device's parent goes into runtime suspend at the wrong time, * it won't be possible to resume the device. To prevent this we @@ -1973,8 +1969,7 @@ unlock: */ spin_lock_irq(&dev->power.lock); dev->power.direct_complete = state.event == PM_EVENT_SUSPEND && - ((pm_runtime_suspended(dev) && ret > 0) || - dev->power.no_pm_callbacks) && + (ret > 0 || dev->power.no_pm_callbacks) && !dev_pm_test_driver_flags(dev, DPM_FLAG_NEVER_SKIP); spin_unlock_irq(&dev->power.lock); return 0; diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index bff5295016ae..c3e6bd59e920 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -37,10 +37,12 @@ config CPU_FREQ_STAT choice prompt "Default CPUFreq governor" default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ + default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if BIG_LITTLE + default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP default CPU_FREQ_DEFAULT_GOV_PERFORMANCE help This option sets which CPUFreq governor shall be loaded at - startup. If in doubt, select 'performance'. + startup. If in doubt, use the default setting. config CPU_FREQ_DEFAULT_GOV_PERFORMANCE bool "performance" diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86 index 62502d0e4c33..bc58a0809d11 100644 --- a/drivers/cpufreq/Kconfig.x86 +++ b/drivers/cpufreq/Kconfig.x86 @@ -8,6 +8,8 @@ config X86_INTEL_PSTATE depends on X86 select ACPI_PROCESSOR if ACPI select ACPI_CPPC_LIB if X86_64 && ACPI && SCHED_MC_PRIO + select CPU_FREQ_GOV_PERFORMANCE + select CPU_FREQ_GOV_SCHEDUTIL if SMP help This driver provides a P state for Intel core processors. The driver implements an internal governor and will become diff --git a/drivers/platform/x86/intel_int0002_vgpio.c b/drivers/platform/x86/intel_int0002_vgpio.c index 7b23efc46a43..289c6655d425 100644 --- a/drivers/platform/x86/intel_int0002_vgpio.c +++ b/drivers/platform/x86/intel_int0002_vgpio.c @@ -127,6 +127,14 @@ static irqreturn_t int0002_irq(int irq, void *data) return IRQ_HANDLED; } +static bool int0002_check_wake(void *data) +{ + u32 gpe_sts_reg; + + gpe_sts_reg = inl(GPE0A_STS_PORT); + return (gpe_sts_reg & GPE0A_PME_B0_STS_BIT); +} + static struct irq_chip int0002_byt_irqchip = { .name = DRV_NAME, .irq_ack = int0002_irq_ack, @@ -220,6 +228,7 @@ static int int0002_probe(struct platform_device *pdev) return ret; } + acpi_register_wakeup_handler(irq, int0002_check_wake, NULL); device_init_wakeup(dev, true); return 0; } @@ -227,6 +236,7 @@ static int int0002_probe(struct platform_device *pdev) static int int0002_remove(struct platform_device *pdev) { device_init_wakeup(&pdev->dev, false); + acpi_unregister_wakeup_handler(int0002_check_wake, NULL); return 0; } diff --git a/include/linux/acpi.h b/include/linux/acpi.h index b7d3caf6f205..9f70b7807d53 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -488,6 +488,11 @@ void __init acpi_nvs_nosave_s3(void); void __init acpi_sleep_no_blacklist(void); #endif /* CONFIG_PM_SLEEP */ +int acpi_register_wakeup_handler( + int wake_irq, bool (*wakeup)(void *context), void *context); +void acpi_unregister_wakeup_handler( + bool (*wakeup)(void *context), void *context); + struct acpi_osc_context { char *uuid_str; /* UUID string */ int rev; diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 6dbeedb7354c..86aba8706b16 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -678,7 +678,7 @@ static int load_image_and_restore(void) error = swsusp_read(&flags); swsusp_close(FMODE_READ); if (!error) - hibernation_restore(flags & SF_PLATFORM_MODE); + error = hibernation_restore(flags & SF_PLATFORM_MODE); pr_err("Failed to load image, recovering.\n"); swsusp_free(); diff --git a/kernel/power/main.c b/kernel/power/main.c index 69b7a8aeca3b..40f86ec4ab30 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -535,6 +535,13 @@ static ssize_t pm_debug_messages_store(struct kobject *kobj, power_attr(pm_debug_messages); +static int __init pm_debug_messages_setup(char *str) +{ + pm_debug_messages_on = true; + return 1; +} +__setup("pm_debug_messages", pm_debug_messages_setup); + /** * __pm_pr_dbg - Print a suspend debug message to the kernel log. * @defer: Whether or not to use printk_deferred() to print the message. |