From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: [PATCH 1/3] PM / core: Add SAFE_SUSPEND driver flag Date: Tue, 29 Aug 2017 02:20:11 +0200 Message-ID: <35841101.LqGbCjJMGH@aspire.rjw.lan> References: <1503499329-28834-1-git-send-email-ulf.hansson@linaro.org> <4245176.X6JjkhnUAM@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <4245176.X6JjkhnUAM@aspire.rjw.lan> Sender: linux-pm-owner@vger.kernel.org To: Ulf Hansson Cc: Wolfram Sang , Len Brown , linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, Kevin Hilman , Jarkko Nikula , Andy Shevchenko , Mika Westerberg , Jisheng Zhang , John Stultz , Guodong Xu , Sumit Semwal , Haojian Zhuang , linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, Greg Kroah-Hartman List-Id: linux-acpi@vger.kernel.org From: Rafael J. Wysocki Add a driver_flags field to struct dev_pm_info for flags that can be set by device drivers at the probe time to inform the PM core and/or bus types, PM domains and so on on the capabilities and/or preferences of device drivers. It is anticipated that more than one flag of this kind will be necessary going forward. Define and document a SAFE_SUSPEND flag to instruct bus types and PM domains that the system suspend callbacks provided by the driver can cope with runtime suspended devices, so from the driver's perspective it should be safe to leave devices in runtime suspend during system suspend. Signed-off-by: Rafael J. Wysocki --- Documentation/driver-api/pm/devices.rst | 7 +++++++ drivers/base/dd.c | 2 ++ include/linux/pm.h | 16 ++++++++++++++++ 3 files changed, 25 insertions(+) Index: linux-pm/include/linux/pm.h =================================================================== --- linux-pm.orig/include/linux/pm.h +++ linux-pm/include/linux/pm.h @@ -550,6 +550,21 @@ 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. + * + * SAFE_SUSPEND: No need to runtime resume the device during system suspend. + * + * Setting SAFE_SUSPEND instructs bus types and PM domains which may want to + * runtime resume the device upfront during system suspend that doing so is not + * necessary from the driver's perspective, because the system suspend callbacks + * provided by it can cope with a runtime suspended device. + */ +#define DPM_FLAG_SAFE_SUSPEND BIT(0) + struct dev_pm_info { pm_message_t power_state; unsigned int can_wakeup:1; @@ -561,6 +576,7 @@ 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 */ + unsigned int driver_flags; spinlock_t lock; #ifdef CONFIG_PM_SLEEP struct list_head entry; Index: linux-pm/drivers/base/dd.c =================================================================== --- linux-pm.orig/drivers/base/dd.c +++ linux-pm/drivers/base/dd.c @@ -436,6 +436,7 @@ pinctrl_bind_failed: if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); + dev->power.driver_flags = 0; switch (ret) { case -EPROBE_DEFER: @@ -841,6 +842,7 @@ static void __device_release_driver(stru if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); + dev->power.driver_flags = 0; klist_remove(&dev->p->knode_driver); device_pm_check_callbacks(dev); Index: linux-pm/Documentation/driver-api/pm/devices.rst =================================================================== --- linux-pm.orig/Documentation/driver-api/pm/devices.rst +++ linux-pm/Documentation/driver-api/pm/devices.rst @@ -729,6 +729,13 @@ state temporarily, for example so that i disabled. This all depends on the hardware and the design of the subsystem and device driver in question. +Some bus types and PM domains have a policy to runtime resume all +devices upfront in their ``->suspend`` callbacks, but that may not be really +necessary if the system suspend-resume callbacks provided by the device's +driver can cope with a runtime-suspended device. The driver can indicate that +by setting ``DPM_FLAG_SAFE_SUSPEND`` in :c:member:`power.driver_flags` at the +probe time. + During system-wide resume from a sleep state it's easiest to put devices into the full-power state, as explained in :file:`Documentation/power/runtime_pm.txt`. Refer to that document for more information regarding this particular issue as From mboxrd@z Thu Jan 1 00:00:00 1970 From: rjw@rjwysocki.net (Rafael J. Wysocki) Date: Tue, 29 Aug 2017 02:20:11 +0200 Subject: [PATCH 1/3] PM / core: Add SAFE_SUSPEND driver flag In-Reply-To: <4245176.X6JjkhnUAM@aspire.rjw.lan> References: <1503499329-28834-1-git-send-email-ulf.hansson@linaro.org> <4245176.X6JjkhnUAM@aspire.rjw.lan> Message-ID: <35841101.LqGbCjJMGH@aspire.rjw.lan> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Rafael J. Wysocki Add a driver_flags field to struct dev_pm_info for flags that can be set by device drivers at the probe time to inform the PM core and/or bus types, PM domains and so on on the capabilities and/or preferences of device drivers. It is anticipated that more than one flag of this kind will be necessary going forward. Define and document a SAFE_SUSPEND flag to instruct bus types and PM domains that the system suspend callbacks provided by the driver can cope with runtime suspended devices, so from the driver's perspective it should be safe to leave devices in runtime suspend during system suspend. Signed-off-by: Rafael J. Wysocki --- Documentation/driver-api/pm/devices.rst | 7 +++++++ drivers/base/dd.c | 2 ++ include/linux/pm.h | 16 ++++++++++++++++ 3 files changed, 25 insertions(+) Index: linux-pm/include/linux/pm.h =================================================================== --- linux-pm.orig/include/linux/pm.h +++ linux-pm/include/linux/pm.h @@ -550,6 +550,21 @@ 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. + * + * SAFE_SUSPEND: No need to runtime resume the device during system suspend. + * + * Setting SAFE_SUSPEND instructs bus types and PM domains which may want to + * runtime resume the device upfront during system suspend that doing so is not + * necessary from the driver's perspective, because the system suspend callbacks + * provided by it can cope with a runtime suspended device. + */ +#define DPM_FLAG_SAFE_SUSPEND BIT(0) + struct dev_pm_info { pm_message_t power_state; unsigned int can_wakeup:1; @@ -561,6 +576,7 @@ 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 */ + unsigned int driver_flags; spinlock_t lock; #ifdef CONFIG_PM_SLEEP struct list_head entry; Index: linux-pm/drivers/base/dd.c =================================================================== --- linux-pm.orig/drivers/base/dd.c +++ linux-pm/drivers/base/dd.c @@ -436,6 +436,7 @@ pinctrl_bind_failed: if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); + dev->power.driver_flags = 0; switch (ret) { case -EPROBE_DEFER: @@ -841,6 +842,7 @@ static void __device_release_driver(stru if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); + dev->power.driver_flags = 0; klist_remove(&dev->p->knode_driver); device_pm_check_callbacks(dev); Index: linux-pm/Documentation/driver-api/pm/devices.rst =================================================================== --- linux-pm.orig/Documentation/driver-api/pm/devices.rst +++ linux-pm/Documentation/driver-api/pm/devices.rst @@ -729,6 +729,13 @@ state temporarily, for example so that i disabled. This all depends on the hardware and the design of the subsystem and device driver in question. +Some bus types and PM domains have a policy to runtime resume all +devices upfront in their ``->suspend`` callbacks, but that may not be really +necessary if the system suspend-resume callbacks provided by the device's +driver can cope with a runtime-suspended device. The driver can indicate that +by setting ``DPM_FLAG_SAFE_SUSPEND`` in :c:member:`power.driver_flags` at the +probe time. + During system-wide resume from a sleep state it's easiest to put devices into the full-power state, as explained in :file:`Documentation/power/runtime_pm.txt`. Refer to that document for more information regarding this particular issue as