From cf579dfb82550e34de7ccf3ef090d8b834ccd3a9 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 29 Jan 2012 20:38:29 +0100 Subject: PM / Sleep: Introduce "late suspend" and "early resume" of devices The current device suspend/resume phases during system-wide power transitions appear to be insufficient for some platforms that want to use the same callback routines for saving device states and related operations during runtime suspend/resume as well as during system suspend/resume. In principle, they could point their .suspend_noirq() and .resume_noirq() to the same callback routines as their .runtime_suspend() and .runtime_resume(), respectively, but at least some of them require device interrupts to be enabled while the code in those routines is running. It also makes sense to have device suspend-resume callbacks that will be executed with runtime PM disabled and with device interrupts enabled in case someone needs to run some special code in that context during system-wide power transitions. Apart from this, .suspend_noirq() and .resume_noirq() were introduced as a workaround for drivers using shared interrupts and failing to prevent their interrupt handlers from accessing suspended hardware. It appears to be better not to use them for other porposes, or we may have to deal with some serious confusion (which seems to be happening already). For the above reasons, introduce new device suspend/resume phases, "late suspend" and "early resume" (and analogously for hibernation) whose callback will be executed with runtime PM disabled and with device interrupts enabled and whose callback pointers generally may point to runtime suspend/resume routines. Signed-off-by: Rafael J. Wysocki Reviewed-by: Mark Brown Reviewed-by: Kevin Hilman --- include/linux/pm.h | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) (limited to 'include/linux/pm.h') diff --git a/include/linux/pm.h b/include/linux/pm.h index e4982ac3fbbc..c68e1f22ac95 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -110,6 +110,10 @@ typedef struct pm_message { * Subsystem-level @suspend() is executed for all devices after invoking * subsystem-level @prepare() for all of them. * + * @suspend_late: Continue operations started by @suspend(). For a number of + * devices @suspend_late() may point to the same callback routine as the + * runtime suspend callback. + * * @resume: Executed after waking the system up from a sleep state in which the * contents of main memory were preserved. The exact action to perform * depends on the device's subsystem, but generally the driver is expected @@ -122,6 +126,10 @@ typedef struct pm_message { * Subsystem-level @resume() is executed for all devices after invoking * subsystem-level @resume_noirq() for all of them. * + * @resume_early: Prepare to execute @resume(). For a number of devices + * @resume_early() may point to the same callback routine as the runtime + * resume callback. + * * @freeze: Hibernation-specific, executed before creating a hibernation image. * Analogous to @suspend(), but it should not enable the device to signal * wakeup events or change its power state. The majority of subsystems @@ -131,6 +139,10 @@ typedef struct pm_message { * Subsystem-level @freeze() is executed for all devices after invoking * subsystem-level @prepare() for all of them. * + * @freeze_late: Continue operations started by @freeze(). Analogous to + * @suspend_late(), but it should not enable the device to signal wakeup + * events or change its power state. + * * @thaw: Hibernation-specific, executed after creating a hibernation image OR * if the creation of an image has failed. Also executed after a failing * attempt to restore the contents of main memory from such an image. @@ -140,15 +152,23 @@ typedef struct pm_message { * subsystem-level @thaw_noirq() for all of them. It also may be executed * directly after @freeze() in case of a transition error. * + * @thaw_early: Prepare to execute @thaw(). Undo the changes made by the + * preceding @freeze_late(). + * * @poweroff: Hibernation-specific, executed after saving a hibernation image. * Analogous to @suspend(), but it need not save the device's settings in * memory. * Subsystem-level @poweroff() is executed for all devices after invoking * subsystem-level @prepare() for all of them. * + * @poweroff_late: Continue operations started by @poweroff(). Analogous to + * @suspend_late(), but it need not save the device's settings in memory. + * * @restore: Hibernation-specific, executed after restoring the contents of main * memory from a hibernation image, analogous to @resume(). * + * @restore_early: Prepare to execute @restore(), analogous to @resume_early(). + * * @suspend_noirq: Complete the actions started by @suspend(). Carry out any * additional operations required for suspending the device that might be * racing with its driver's interrupt handler, which is guaranteed not to @@ -158,9 +178,10 @@ typedef struct pm_message { * @suspend_noirq() has returned successfully. If the device can generate * system wakeup signals and is enabled to wake up the system, it should be * configured to do so at that time. However, depending on the platform - * and device's subsystem, @suspend() may be allowed to put the device into - * the low-power state and configure it to generate wakeup signals, in - * which case it generally is not necessary to define @suspend_noirq(). + * and device's subsystem, @suspend() or @suspend_late() may be allowed to + * put the device into the low-power state and configure it to generate + * wakeup signals, in which case it generally is not necessary to define + * @suspend_noirq(). * * @resume_noirq: Prepare for the execution of @resume() by carrying out any * operations required for resuming the device that might be racing with @@ -171,9 +192,9 @@ typedef struct pm_message { * additional operations required for freezing the device that might be * racing with its driver's interrupt handler, which is guaranteed not to * run while @freeze_noirq() is being executed. - * The power state of the device should not be changed by either @freeze() - * or @freeze_noirq() and it should not be configured to signal system - * wakeup by any of these callbacks. + * The power state of the device should not be changed by either @freeze(), + * or @freeze_late(), or @freeze_noirq() and it should not be configured to + * signal system wakeup by any of these callbacks. * * @thaw_noirq: Prepare for the execution of @thaw() by carrying out any * operations required for thawing the device that might be racing with its @@ -249,6 +270,12 @@ struct dev_pm_ops { int (*thaw)(struct device *dev); int (*poweroff)(struct device *dev); int (*restore)(struct device *dev); + int (*suspend_late)(struct device *dev); + int (*resume_early)(struct device *dev); + int (*freeze_late)(struct device *dev); + int (*thaw_early)(struct device *dev); + int (*poweroff_late)(struct device *dev); + int (*restore_early)(struct device *dev); int (*suspend_noirq)(struct device *dev); int (*resume_noirq)(struct device *dev); int (*freeze_noirq)(struct device *dev); @@ -584,13 +611,13 @@ struct dev_pm_domain { #ifdef CONFIG_PM_SLEEP extern void device_pm_lock(void); -extern void dpm_resume_noirq(pm_message_t state); +extern void dpm_resume_start(pm_message_t state); extern void dpm_resume_end(pm_message_t state); extern void dpm_resume(pm_message_t state); extern void dpm_complete(pm_message_t state); extern void device_pm_unlock(void); -extern int dpm_suspend_noirq(pm_message_t state); +extern int dpm_suspend_end(pm_message_t state); extern int dpm_suspend_start(pm_message_t state); extern int dpm_suspend(pm_message_t state); extern int dpm_prepare(pm_message_t state); -- cgit v1.2.3 From e470d06655e00749f6f9372e4fa4f20cea7ed7c5 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 29 Jan 2012 20:38:41 +0100 Subject: PM / Sleep: Introduce generic callbacks for new device PM phases Introduce generic subsystem callbacks for the new phases of device suspend/resume during system power transitions: "late suspend", "early resume", "late freeze", "early thaw", "late poweroff", "early restore". Signed-off-by: Rafael J. Wysocki --- include/linux/pm.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/pm.h') diff --git a/include/linux/pm.h b/include/linux/pm.h index c68e1f22ac95..73c610573a74 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -632,17 +632,23 @@ extern void __suspend_report_result(const char *function, void *fn, int ret); extern int device_pm_wait_for_dev(struct device *sub, struct device *dev); extern int pm_generic_prepare(struct device *dev); +extern int pm_generic_suspend_late(struct device *dev); extern int pm_generic_suspend_noirq(struct device *dev); extern int pm_generic_suspend(struct device *dev); +extern int pm_generic_resume_early(struct device *dev); extern int pm_generic_resume_noirq(struct device *dev); extern int pm_generic_resume(struct device *dev); extern int pm_generic_freeze_noirq(struct device *dev); +extern int pm_generic_freeze_late(struct device *dev); extern int pm_generic_freeze(struct device *dev); extern int pm_generic_thaw_noirq(struct device *dev); +extern int pm_generic_thaw_early(struct device *dev); extern int pm_generic_thaw(struct device *dev); extern int pm_generic_restore_noirq(struct device *dev); +extern int pm_generic_restore_early(struct device *dev); extern int pm_generic_restore(struct device *dev); extern int pm_generic_poweroff_noirq(struct device *dev); +extern int pm_generic_poweroff_late(struct device *dev); extern int pm_generic_poweroff(struct device *dev); extern void pm_generic_complete(struct device *dev); -- cgit v1.2.3 From c48825251cf5950da9d618144c4db6c130e6c0cd Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 13 Feb 2012 16:29:47 +0100 Subject: PM: Add comment describing relationships between PM callbacks to pm.h The UNIVERSAL_DEV_PM_OPS() macro is slightly misleading, because it may suggest that it's a good idea to point runtime PM callback pointers to the same routines as system suspend/resume callbacks .suspend() and .resume(), which is not the case. For this reason, add a comment to include/linux/pm.h, next to the definition of UNIVERSAL_DEV_PM_OPS(), describing how device PM callbacks are related to each other. Signed-off-by: Rafael J. Wysocki --- include/linux/pm.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux/pm.h') diff --git a/include/linux/pm.h b/include/linux/pm.h index 73c610573a74..d6dd6f612b8d 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -320,6 +320,15 @@ const struct dev_pm_ops name = { \ /* * Use this for defining a set of PM operations to be used in all situations * (sustem suspend, hibernation or runtime PM). + * NOTE: In general, system suspend callbacks, .suspend() and .resume(), should + * be different from the corresponding runtime PM callbacks, .runtime_suspend(), + * and .runtime_resume(), because .runtime_suspend() always works on an already + * quiescent device, while .suspend() should assume that the device may be doing + * something when it is called (it should ensure that the device will be + * quiescent after it has returned). Therefore it's better to point the "late" + * suspend and "early" resume callback pointers, .suspend_late() and + * .resume_early(), to the same routines as .runtime_suspend() and + * .runtime_resume(), respectively (and analogously for hibernation). */ #define UNIVERSAL_DEV_PM_OPS(name, suspend_fn, resume_fn, idle_fn) \ const struct dev_pm_ops name = { \ -- cgit v1.2.3 From 85dc0b8a4019e38ad4fd0c008f89a5c241805ac2 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 13 Mar 2012 01:01:39 +0100 Subject: PM / QoS: Make it possible to expose PM QoS latency constraints A runtime suspend of a device (e.g. an MMC controller) belonging to a power domain or, in a more complicated scenario, a runtime suspend of another device in the same power domain, may cause power to be removed from the entire domain. In that case, the amount of time necessary to runtime-resume the given device (e.g. the MMC controller) is often substantially greater than the time needed to run its driver's runtime resume callback. That may hurt performance in some situations, because user data may need to wait for the device to become operational, so we should make it possible to prevent that from happening. For this reason, introduce a new sysfs attribute for devices, power/pm_qos_resume_latency_us, allowing user space to specify the upper bound of the time necessary to bring the (runtime-suspended) device up after the resume of it has been requested. However, make that attribute appear only for the devices whose drivers declare support for it by calling the (new) dev_pm_qos_expose_latency_limit() helper function with the appropriate initial value of the attribute. Signed-off-by: Rafael J. Wysocki Reviewed-by: Kevin Hilman Reviewed-by: Mark Brown Acked-by: Linus Walleij --- include/linux/pm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/pm.h') diff --git a/include/linux/pm.h b/include/linux/pm.h index 73c610573a74..4db39ed1a6ef 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -537,6 +537,7 @@ struct dev_pm_info { unsigned long accounting_timestamp; ktime_t suspend_time; s64 max_time_suspended_ns; + struct dev_pm_qos_request *pq_req; #endif struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */ struct pm_qos_constraints *constraints; -- cgit v1.2.3