diff options
| -rw-r--r-- | Documentation/driver-api/pm/devices.rst | 14 | ||||
| -rw-r--r-- | Documentation/power/pci.txt | 19 | ||||
| -rw-r--r-- | drivers/acpi/device_pm.c | 13 | ||||
| -rw-r--r-- | drivers/base/dd.c | 2 | ||||
| -rw-r--r-- | drivers/base/power/main.c | 4 | ||||
| -rw-r--r-- | drivers/pci/pci-driver.c | 5 | ||||
| -rw-r--r-- | include/linux/device.h | 10 | ||||
| -rw-r--r-- | include/linux/pm.h | 20 |
8 files changed, 81 insertions, 6 deletions
diff --git a/Documentation/driver-api/pm/devices.rst b/Documentation/driver-api/pm/devices.rst index 4a18ef9997c0..8add5b302a89 100644 --- a/Documentation/driver-api/pm/devices.rst +++ b/Documentation/driver-api/pm/devices.rst @@ -354,6 +354,20 @@ the phases are: ``prepare``, ``suspend``, ``suspend_late``, ``suspend_noirq``. is because all such devices are initially set to runtime-suspended with runtime PM disabled. + This feature also can be controlled by device drivers by using the + ``DPM_FLAG_NEVER_SKIP`` and ``DPM_FLAG_SMART_PREPARE`` driver power + management flags. [Typically, they are set at the time the driver is + probed against the device in question by passing them to the + :c:func:`dev_pm_set_driver_flags` helper function.] If the first of + these flags is set, the PM core will not apply the direct-complete + procedure described above to the given device and, consequenty, to any + of its ancestors. The second flag, when set, informs the middle layer + code (bus types, device types, PM domains, classes) that it should take + the return value of the ``->prepare`` callback provided by the driver + into account and it may only return a positive value from its own + ``->prepare`` callback if the driver's one also has returned a positive + value. + 2. The ``->suspend`` methods should quiesce the device to stop it from performing I/O. They also may save the device registers and put it into the appropriate low-power state, depending on the bus type the device is diff --git a/Documentation/power/pci.txt b/Documentation/power/pci.txt index a1b7f7158930..ab4e7d0540c1 100644 --- a/Documentation/power/pci.txt +++ b/Documentation/power/pci.txt @@ -961,6 +961,25 @@ dev_pm_ops to indicate that one suspend routine is to be pointed to by the .suspend(), .freeze(), and .poweroff() members and one resume routine is to be pointed to by the .resume(), .thaw(), and .restore() members. +3.1.19. Driver Flags for Power Management + +The PM core allows device drivers to set flags that influence the handling of +power management for the devices by the core itself and by middle layer code +including the PCI bus type. The flags should be set once at the driver probe +time with the help of the dev_pm_set_driver_flags() function and they should not +be updated directly afterwards. + +The DPM_FLAG_NEVER_SKIP flag prevents the PM core from using the direct-complete +mechanism allowing device suspend/resume callbacks to be skipped if the device +is in runtime suspend when the system suspend starts. That also affects all of +the ancestors of the device, so this flag should only be used if absolutely +necessary. + +The DPM_FLAG_SMART_PREPARE flag instructs the PCI bus type to only return a +positive value from pci_pm_prepare() if the ->prepare callback provided by the +driver of the device returns a positive value. That allows the driver to opt +out from using the direct-complete mechanism dynamically. + 3.2. Device Runtime Power Management ------------------------------------ In addition to providing device power management callbacks PCI device drivers diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c index 17e8eb93a76c..b4dcc6144e6b 100644 --- a/drivers/acpi/device_pm.c +++ b/drivers/acpi/device_pm.c @@ -959,11 +959,16 @@ static bool acpi_dev_needs_resume(struct device *dev, struct acpi_device *adev) int acpi_subsys_prepare(struct device *dev) { struct acpi_device *adev = ACPI_COMPANION(dev); - int ret; - ret = pm_generic_prepare(dev); - if (ret < 0) - return ret; + if (dev->driver && dev->driver->pm && dev->driver->pm->prepare) { + int ret = dev->driver->pm->prepare(dev); + + if (ret < 0) + return ret; + + if (!ret && dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_PREPARE)) + return 0; + } if (!adev || !pm_runtime_suspended(dev)) return 0; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index ad44b40fe284..45575e134696 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -464,6 +464,7 @@ pinctrl_bind_failed: if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); + dev_pm_set_driver_flags(dev, 0); switch (ret) { case -EPROBE_DEFER: @@ -869,6 +870,7 @@ static void __device_release_driver(struct device *dev, struct device *parent) if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); + dev_pm_set_driver_flags(dev, 0); klist_remove(&dev->p->knode_driver); device_pm_check_callbacks(dev); diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 9bbbbb13a9db..c0135cd95ada 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1700,7 +1700,9 @@ unlock: * applies to suspend transitions, however. */ spin_lock_irq(&dev->power.lock); - dev->power.direct_complete = ret > 0 && state.event == PM_EVENT_SUSPEND; + dev->power.direct_complete = state.event == PM_EVENT_SUSPEND && + pm_runtime_suspended(dev) && ret > 0 && + !dev_pm_test_driver_flags(dev, DPM_FLAG_NEVER_SKIP); spin_unlock_irq(&dev->power.lock); return 0; } diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 11bd267fc137..68a32703b30a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -689,8 +689,11 @@ static int pci_pm_prepare(struct device *dev) if (drv && drv->pm && drv->pm->prepare) { int error = drv->pm->prepare(dev); - if (error) + if (error < 0) return error; + + if (!error && dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_PREPARE)) + return 0; } return pci_dev_keep_suspended(to_pci_dev(dev)); } diff --git a/include/linux/device.h b/include/linux/device.h index c32e6f974d4a..fb9451599aca 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1070,6 +1070,16 @@ static inline void dev_pm_syscore_device(struct device *dev, bool val) #endif } +static inline void dev_pm_set_driver_flags(struct device *dev, u32 flags) +{ + dev->power.driver_flags = flags; +} + +static inline bool dev_pm_test_driver_flags(struct device *dev, u32 flags) +{ + return !!(dev->power.driver_flags & flags); +} + static inline void device_lock(struct device *dev) { mutex_lock(&dev->mutex); diff --git a/include/linux/pm.h b/include/linux/pm.h index a0ceeccf2846..f10bad831bfa 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -550,6 +550,25 @@ struct pm_subsys_data { #endif }; +/* + * Driver flags to control system suspend/resume behavior. + * + * These flags can be set by device drivers at the probe time. They need not be + * cleared by the drivers as the driver core will take care of that. + * + * NEVER_SKIP: Do not skip system suspend/resume callbacks for the device. + * SMART_PREPARE: Check the return value of the driver's ->prepare callback. + * + * Setting SMART_PREPARE instructs bus types and PM domains which may want + * system suspend/resume callbacks to be skipped for the device to return 0 from + * their ->prepare callbacks if the driver's ->prepare callback returns 0 (in + * other words, the system suspend/resume callbacks can only be skipped for the + * device if its driver doesn't object against that). This flag has no effect + * if NEVER_SKIP is set. + */ +#define DPM_FLAG_NEVER_SKIP BIT(0) +#define DPM_FLAG_SMART_PREPARE BIT(1) + struct dev_pm_info { pm_message_t power_state; unsigned int can_wakeup:1; @@ -561,6 +580,7 @@ struct dev_pm_info { bool is_late_suspended:1; bool early_init:1; /* Owned by the PM core */ bool direct_complete:1; /* Owned by the PM core */ + u32 driver_flags; spinlock_t lock; #ifdef CONFIG_PM_SLEEP struct list_head entry; |