From 471a739a47aa7d582f0cdf9d392957d04632bae2 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 26 Jun 2019 00:20:23 +0200 Subject: [PATCH] PCI: PM: Avoid skipping bus-level PM on platforms without ACPI There are platforms that do not call pm_set_suspend_via_firmware(), so pm_suspend_via_firmware() returns 'false' on them, but the power states of PCI devices (PCIe ports in particular) are changed as a result of powering down core platform components during system-wide suspend. Thus the pm_suspend_via_firmware() checks in pci_pm_suspend_noirq() and pci_pm_resume_noirq() introduced by commit 3e26c5feed2a ("PCI: PM: Skip devices in D0 for suspend-to- idle") are not sufficient to determine that devices left in D0 during suspend will remain in D0 during resume and so the bus-level power management can be skipped for them. For this reason, introduce a new global suspend flag, PM_SUSPEND_FLAG_NO_PLATFORM, set it for suspend-to-idle only and replace the pm_suspend_via_firmware() checks mentioned above with checks against this flag. Fixes: 3e26c5feed2a ("PCI: PM: Skip devices in D0 for suspend-to-idle") Reported-by: Jon Hunter Tested-by: Jon Hunter Signed-off-by: Rafael J. Wysocki Tested-by: Mika Westerberg Reviewed-by: Mika Westerberg --- drivers/pci/pci-driver.c | 8 ++++---- include/linux/suspend.h | 26 ++++++++++++++++++++++++-- kernel/power/suspend.c | 3 +++ 3 files changed, 31 insertions(+), 6 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 98af9ecd4a90..ca3793002e2f 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -859,7 +859,7 @@ static int pci_pm_suspend_noirq(struct device *dev) pci_dev->bus->self->skip_bus_pm = true; } - if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) { + if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) { dev_dbg(dev, "PCI PM: Skipped\n"); goto Fixup; } @@ -914,10 +914,10 @@ static int pci_pm_resume_noirq(struct device *dev) /* * In the suspend-to-idle case, devices left in D0 during suspend will * stay in D0, so it is not necessary to restore or update their - * configuration here and attempting to put them into D0 again may - * confuse some firmware, so avoid doing that. + * configuration here and attempting to put them into D0 again is + * pointless, so avoid doing that. */ - if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware()) + if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform())) pci_pm_default_resume_early(pci_dev); pci_fixup_device(pci_fixup_resume_early, pci_dev); diff --git a/include/linux/suspend.h b/include/linux/suspend.h index 8594001e8be8..f0d262ad7b78 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -209,8 +209,9 @@ extern int suspend_valid_only_mem(suspend_state_t state); extern unsigned int pm_suspend_global_flags; -#define PM_SUSPEND_FLAG_FW_SUSPEND (1 << 0) -#define PM_SUSPEND_FLAG_FW_RESUME (1 << 1) +#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0) +#define PM_SUSPEND_FLAG_FW_RESUME BIT(1) +#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2) static inline void pm_suspend_clear_flags(void) { @@ -227,6 +228,11 @@ static inline void pm_set_resume_via_firmware(void) pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME; } +static inline void pm_set_suspend_no_platform(void) +{ + pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM; +} + /** * pm_suspend_via_firmware - Check if platform firmware will suspend the system. * @@ -268,6 +274,22 @@ static inline bool pm_resume_via_firmware(void) return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME); } +/** + * pm_suspend_no_platform - Check if platform may change device power states. + * + * To be called during system-wide power management transitions to sleep states + * or during the subsequent system-wide transitions back to the working state. + * + * Return 'true' if the power states of devices remain under full control of the + * kernel throughout the system-wide suspend and resume cycle in progress (that + * is, if a device is put into a certain power state during suspend, it can be + * expected to remain in that state during resume). + */ +static inline bool pm_suspend_no_platform(void) +{ + return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM); +} + /* Suspend-to-idle state machnine. */ enum s2idle_states { S2IDLE_STATE_NONE, /* Not suspended/suspending. */ diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 9505101ed2bc..096211299c07 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -493,6 +493,9 @@ int suspend_devices_and_enter(suspend_state_t state) pm_suspend_target_state = state; + if (state == PM_SUSPEND_TO_IDLE) + pm_set_suspend_no_platform(); + error = platform_suspend_begin(state); if (error) goto Close;