From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: [PATCH 06/12] PCI / PM: Take SMART_SUSPEND driver flag into account Date: Mon, 16 Oct 2017 03:29:47 +0200 Message-ID: <12906785.qsTjxC3pk6@aspire.rjw.lan> References: <3806130.B2KCK0tvef@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <3806130.B2KCK0tvef@aspire.rjw.lan> Sender: linux-pm-owner@vger.kernel.org To: Linux PM Cc: Bjorn Helgaas , Alan Stern , Greg Kroah-Hartman , LKML , Linux ACPI , Linux PCI , Linux Documentation , Mika Westerberg , Ulf Hansson , Andy Shevchenko , Kevin Hilman , Wolfram Sang , linux-i2c@vger.kernel.org, Lee Jones List-Id: linux-acpi@vger.kernel.org From: Rafael J. Wysocki Make the PCI bus type take DPM_FLAG_SMART_SUSPEND into account in its system suspend callbacks and make sure that all code that should not run in parallel with pci_pm_runtime_resume() is executed in the "late" phases of system suspend, freeze and poweroff transitions. [Note that the pm_runtime_suspended() check in pci_dev_keep_suspended() is an optimization, because if is not passed, all of the subsequent checks may be skipped and some of them are much more overhead in general.] Signed-off-by: Rafael J. Wysocki --- --- Documentation/power/pci.txt | 6 ++++ drivers/pci/pci-driver.c | 56 ++++++++++++++++++++++++++++++-------------- 2 files changed, 45 insertions(+), 17 deletions(-) Index: linux-pm/drivers/pci/pci-driver.c =================================================================== --- linux-pm.orig/drivers/pci/pci-driver.c +++ linux-pm/drivers/pci/pci-driver.c @@ -727,18 +727,25 @@ static int pci_pm_suspend(struct device if (!pm) { pci_pm_default_suspend(pci_dev); - goto Fixup; + return 0; } /* - * PCI devices suspended at run time need to be resumed at this point, - * because in general it is necessary to reconfigure them for system - * suspend. Namely, if the device is supposed to wake up the system - * from the sleep state, we may need to reconfigure it for this purpose. - * In turn, if the device is not supposed to wake up the system from the - * sleep state, we'll have to prevent it from signaling wake-up. + * PCI devices suspended at run time may need to be resumed at this + * point, because in general it may be necessary to reconfigure them for + * system suspend. Namely, if the device is expected to wake up the + * system from the sleep state, it may have to be reconfigured for this + * purpose, or if the device is not expected to wake up the system from + * the sleep state, it should be prevented from signaling wakeup events + * going forward. + * + * Also if the driver of the device does not indicate that its system + * suspend callbacks can cope with runtime-suspended devices, it is + * better to resume the device from runtime suspend here. */ - pm_runtime_resume(dev); + if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) || + !pci_dev_keep_suspended(pci_dev)) + pm_runtime_resume(dev); pci_dev->state_saved = false; if (pm->suspend) { @@ -758,12 +765,16 @@ static int pci_pm_suspend(struct device } } - Fixup: - pci_fixup_device(pci_fixup_suspend, pci_dev); - return 0; } +static int pci_pm_suspend_late(struct device *dev) +{ + pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev)); + + return pm_generic_suspend_late(dev);; +} + static int pci_pm_suspend_noirq(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); @@ -872,6 +883,7 @@ static int pci_pm_resume(struct device * #else /* !CONFIG_SUSPEND */ #define pci_pm_suspend NULL +#define pci_pm_suspend_late NULL #define pci_pm_suspend_noirq NULL #define pci_pm_resume NULL #define pci_pm_resume_noirq NULL @@ -906,7 +918,8 @@ static int pci_pm_freeze(struct device * * devices should not be touched during freeze/thaw transitions, * however. */ - pm_runtime_resume(dev); + if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND)) + pm_runtime_resume(dev); pci_dev->state_saved = false; if (pm->freeze) { @@ -1004,11 +1017,13 @@ static int pci_pm_poweroff(struct device if (!pm) { pci_pm_default_suspend(pci_dev); - goto Fixup; + return 0; } /* The reason to do that is the same as in pci_pm_suspend(). */ - pm_runtime_resume(dev); + if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) || + !pci_dev_keep_suspended(pci_dev)) + pm_runtime_resume(dev); pci_dev->state_saved = false; if (pm->poweroff) { @@ -1020,12 +1035,16 @@ static int pci_pm_poweroff(struct device return error; } - Fixup: - pci_fixup_device(pci_fixup_suspend, pci_dev); - return 0; } +static int pci_pm_poweroff_late(struct device *dev) +{ + pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev)); + + return pm_generic_poweroff_late(dev); +} + static int pci_pm_poweroff_noirq(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); @@ -1124,6 +1143,7 @@ static int pci_pm_restore(struct device #define pci_pm_thaw NULL #define pci_pm_thaw_noirq NULL #define pci_pm_poweroff NULL +#define pci_pm_poweroff_late NULL #define pci_pm_poweroff_noirq NULL #define pci_pm_restore NULL #define pci_pm_restore_noirq NULL @@ -1239,10 +1259,12 @@ static const struct dev_pm_ops pci_dev_p .prepare = pci_pm_prepare, .complete = pci_pm_complete, .suspend = pci_pm_suspend, + .suspend_late = pci_pm_suspend_late, .resume = pci_pm_resume, .freeze = pci_pm_freeze, .thaw = pci_pm_thaw, .poweroff = pci_pm_poweroff, + .poweroff_late = pci_pm_poweroff_late, .restore = pci_pm_restore, .suspend_noirq = pci_pm_suspend_noirq, .resume_noirq = pci_pm_resume_noirq, Index: linux-pm/Documentation/power/pci.txt =================================================================== --- linux-pm.orig/Documentation/power/pci.txt +++ linux-pm/Documentation/power/pci.txt @@ -980,6 +980,12 @@ positive value from pci_pm_prepare() if driver of the device returns a positive value. That allows the driver to opt out from using the direct-complete mechanism dynamically. +The DPM_FLAG_SMART_SUSPEND flag tells the PCI bus type that from the driver's +perspective the device can be safely left in runtime suspend during system +suspend. That causes pci_pm_suspend(), pci_pm_freeze() and pci_pm_poweroff() +to skip resuming the device from runtime suspend unless there are PCI-specific +reasons for doing that. + 3.2. Device Runtime Power Management ------------------------------------ In addition to providing device power management callbacks PCI device drivers