From aa8c6c93747f7b55fa11e1624fec8ca33763a805 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 16 Jan 2009 21:54:43 +0100 Subject: PCI PM: Restore standard config registers of all devices early There is a problem in our handling of suspend-resume of PCI devices that many of them have their standard config registers restored with interrupts enabled and they are put into the full power state with interrupts enabled as well. This may lead to the following scenario: * an interrupt vector is shared between two or more devices * one device is resumed earlier and generates an interrupt * the interrupt handler of another device tries to handle it and attempts to access the device the config space of which hasn't been restored yet and/or which still is in a low power state * the system crashes as a result To prevent this from happening we should restore the standard configuration registers of all devices with interrupts disabled and we should put them into the D0 power state right after that. Unfortunately, this cannot be done using the existing pci_set_power_state(), because it can sleep. Also, to do it we have to make sure that the config spaces of all devices were actually saved during suspend. Signed-off-by: Rafael J. Wysocki Acked-by: Linus Torvalds Signed-off-by: Jesse Barnes --- drivers/pci/pci-driver.c | 91 ++++++++++++++---------------------------------- 1 file changed, 27 insertions(+), 64 deletions(-) (limited to 'drivers/pci/pci-driver.c') diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index c697f2680856..9de07b75b993 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -355,17 +355,27 @@ static int pci_legacy_suspend(struct device *dev, pm_message_t state) int i = 0; if (drv && drv->suspend) { + pci_dev->state_saved = false; + i = drv->suspend(pci_dev, state); suspend_report_result(drv->suspend, i); - } else { - pci_save_state(pci_dev); - /* - * This is for compatibility with existing code with legacy PM - * support. - */ - pci_pm_set_unknown_state(pci_dev); + if (i) + return i; + + if (pci_dev->state_saved) + goto Fixup; + + if (WARN_ON_ONCE(pci_dev->current_state != PCI_D0)) + goto Fixup; } + pci_save_state(pci_dev); + /* + * This is for compatibility with existing code with legacy PM support. + */ + pci_pm_set_unknown_state(pci_dev); + + Fixup: pci_fixup_device(pci_fixup_suspend, pci_dev); return i; @@ -386,81 +396,34 @@ static int pci_legacy_suspend_late(struct device *dev, pm_message_t state) static int pci_legacy_resume_early(struct device *dev) { - int error = 0; struct pci_dev * pci_dev = to_pci_dev(dev); struct pci_driver * drv = pci_dev->driver; - pci_fixup_device(pci_fixup_resume_early, pci_dev); - - if (drv && drv->resume_early) - error = drv->resume_early(pci_dev); - return error; + return drv && drv->resume_early ? + drv->resume_early(pci_dev) : 0; } static int pci_legacy_resume(struct device *dev) { - int error; struct pci_dev * pci_dev = to_pci_dev(dev); struct pci_driver * drv = pci_dev->driver; pci_fixup_device(pci_fixup_resume, pci_dev); - if (drv && drv->resume) { - error = drv->resume(pci_dev); - } else { - /* restore the PCI config space */ - pci_restore_state(pci_dev); - error = pci_pm_reenable_device(pci_dev); - } - return error; + return drv && drv->resume ? + drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev); } /* Auxiliary functions used by the new power management framework */ -static int pci_restore_standard_config(struct pci_dev *pci_dev) -{ - struct pci_dev *parent = pci_dev->bus->self; - int error = 0; - - /* Check if the device's bus is operational */ - if (!parent || parent->current_state == PCI_D0) { - pci_restore_state(pci_dev); - pci_update_current_state(pci_dev, PCI_D0); - } else { - dev_warn(&pci_dev->dev, "unable to restore config, " - "bridge %s in low power state D%d\n", pci_name(parent), - parent->current_state); - pci_dev->current_state = PCI_UNKNOWN; - error = -EAGAIN; - } - - return error; -} - -static bool pci_is_bridge(struct pci_dev *pci_dev) -{ - return !!(pci_dev->subordinate); -} - static void pci_pm_default_resume_noirq(struct pci_dev *pci_dev) { - if (pci_restore_standard_config(pci_dev)) - pci_fixup_device(pci_fixup_resume_early, pci_dev); + pci_restore_standard_config(pci_dev); + pci_fixup_device(pci_fixup_resume_early, pci_dev); } static int pci_pm_default_resume(struct pci_dev *pci_dev) { - /* - * pci_restore_standard_config() should have been called once already, - * but it would have failed if the device's parent bridge had not been - * in power state D0 at that time. Check it and try again if necessary. - */ - if (pci_dev->current_state == PCI_UNKNOWN) { - int error = pci_restore_standard_config(pci_dev); - if (error) - return error; - } - pci_fixup_device(pci_fixup_resume, pci_dev); if (!pci_is_bridge(pci_dev)) @@ -575,11 +538,11 @@ static int pci_pm_resume_noirq(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; + pci_pm_default_resume_noirq(pci_dev); + if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume_early(dev); - pci_pm_default_resume_noirq(pci_dev); - if (drv && drv->pm && drv->pm->resume_noirq) error = drv->pm->resume_noirq(dev); @@ -730,11 +693,11 @@ static int pci_pm_restore_noirq(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; + pci_pm_default_resume_noirq(pci_dev); + if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume_early(dev); - pci_pm_default_resume_noirq(pci_dev); - if (drv && drv->pm && drv->pm->restore_noirq) error = drv->pm->restore_noirq(dev); -- cgit v1.2.2 From 418e4da33f45fd7bdcce48778b149b780ff730bc Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 26 Jan 2009 21:43:08 +0100 Subject: PCI PM: Fix suspend error paths and testing facility breakage If one of device drivers refuses to suspend by returning error code from its ->suspend() callback, the devices that have already been suspended are resumed by executing their drivers' ->resume() callbacks. Some of these callbacks expect the device's configuration space to be restored if the device has been put into D3 before they are called. Unfortunately, this mechanism has been broken by recent changes moving the restoration of config spaces of some devices (most importantly, USB controllers and HDA Intel) into the resume callbacks executed with interrupts off. Obviously, these callbacks are not invoked in the suspend error path and, as a result, the system cannot be successfully brought back into the working state in case of a suspend error. The same thing happens in the hibernation error path right before putting the system into S4. Similarly, the suspend testing facility associated with the /sys/power/pm_test file is broken, because it uses the very same mechanism that is used in the suspend and hibernation error paths. Fix the breakage by making the PCI core restore the configuration spaces of PCI devices that haven't been restored already before pci_pm_resume() is called for those devices by the PM core. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- drivers/pci/pci-driver.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'drivers/pci/pci-driver.c') diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 9de07b75b993..4884c4840b3d 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -370,6 +370,7 @@ static int pci_legacy_suspend(struct device *dev, pm_message_t state) } pci_save_state(pci_dev); + pci_dev->state_saved = true; /* * This is for compatibility with existing code with legacy PM support. */ @@ -419,6 +420,7 @@ static int pci_legacy_resume(struct device *dev) static void pci_pm_default_resume_noirq(struct pci_dev *pci_dev) { pci_restore_standard_config(pci_dev); + pci_dev->state_saved = false; pci_fixup_device(pci_fixup_resume_early, pci_dev); } @@ -555,6 +557,13 @@ static int pci_pm_resume(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; + /* + * This is necessary for the suspend error path in which resume is + * called without restoring the standard config registers of the device. + */ + if (pci_dev->state_saved) + pci_restore_standard_config(pci_dev); + if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume(dev); @@ -710,6 +719,13 @@ static int pci_pm_restore(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; + /* + * This is necessary for the hibernation error path in which restore is + * called without restoring the standard config registers of the device. + */ + if (pci_dev->state_saved) + pci_restore_standard_config(pci_dev); + if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume(dev); -- cgit v1.2.2 From 545ffd58adc86b8d33449dab44fe81b503a6f81b Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 22 Jan 2009 23:36:56 +0100 Subject: PCI PM: Fix hibernation breakage on EeePC 701 Hibernation breaks on EeePC 701 as a result of attempting to put one of its (driverless) devices into a low power state. Avoid that by not attepmting to power manage driverless devices during hibernation. Signed-off-by: Rafael J. Wysocki Reported-and-tested-by: Alan Jenkins Signed-off-by: Jesse Barnes --- drivers/pci/pci-driver.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/pci/pci-driver.c') diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 4884c4840b3d..ab1d615425a8 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -669,7 +669,10 @@ static int pci_pm_poweroff(struct device *dev) if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_suspend(dev, PMSG_HIBERNATE); - if (drv && drv->pm && drv->pm->poweroff) { + if (!drv || !drv->pm) + return 0; + + if (drv->pm->poweroff) { error = drv->pm->poweroff(dev); suspend_report_result(drv->pm->poweroff, error); } -- cgit v1.2.2