On Friday, May 17, 2019 11:08:50 AM CEST Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <[email protected]> > > If a PCI driver leaves the device handled by it in D0 and calls > pci_save_state() on the device in its ->suspend() or ->suspend_late() > callback, it can expect the device to stay in D0 over the whole > s2idle cycle. However, that may not be the case if there is a > spurious wakeup while the system is suspended, because in that case > pci_pm_suspend_noirq() will run again after pci_pm_resume_noirq() > which calls pci_restore_state(), via pci_pm_default_resume_early(), > so state_saved is cleared and the second iteration of > pci_pm_suspend_noirq() will invoke pci_prepare_to_sleep() which > may change the power state of the device. > > To avoid that, add a new internal flag, skip_bus_pm, that will be set > by pci_pm_suspend_noirq() when it runs for the first time during the > given system suspend-resume cycle if the state of the device has > been saved already and the device is still in D0. Setting that flag > will cause the next iterations of pci_pm_suspend_noirq() to set > state_saved for pci_pm_resume_noirq(), so that it always restores the > device state from the originally saved data, and avoid calling > pci_prepare_to_sleep() for the device. > > Fixes: 33e4f80ee69b ("ACPI / PM: Ignore spurious SCI wakeups from > suspend-to-idle") > Signed-off-by: Rafael J. Wysocki <[email protected]> > --- > drivers/pci/pci-driver.c | 17 ++++++++++++++++- > include/linux/pci.h | 1 + > 2 files changed, 17 insertions(+), 1 deletion(-) > > Index: linux-pm/drivers/pci/pci-driver.c > =================================================================== > --- linux-pm.orig/drivers/pci/pci-driver.c > +++ linux-pm/drivers/pci/pci-driver.c > @@ -734,6 +734,8 @@ static int pci_pm_suspend(struct device > struct pci_dev *pci_dev = to_pci_dev(dev); > const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; > > + pci_dev->skip_bus_pm = false; > + > if (pci_has_legacy_pm_support(pci_dev)) > return pci_legacy_suspend(dev, PMSG_SUSPEND); > > @@ -827,7 +829,20 @@ static int pci_pm_suspend_noirq(struct d > } > } > > - if (!pci_dev->state_saved) { > + if (pci_dev->skip_bus_pm) { > + /* > + * The function is running for the second time in a row without > + * going through full resume, which is possible only during > + * suspend-to-idle in a spurious wakeup case. Moreover, the > + * device was originally left in D0, so its power state should > + * not be changed here and the device register values saved > + * originally should be restored on resume again. > + */ > + pci_dev->state_saved = true; > + } else if (pci_dev->state_saved) { > + if (pci_dev->current_state == PCI_D0) > + pci_dev->skip_bus_pm = true; > + } else { > pci_save_state(pci_dev); > if (pci_power_manageable(pci_dev)) > pci_prepare_to_sleep(pci_dev); > Index: linux-pm/include/linux/pci.h > =================================================================== > --- linux-pm.orig/include/linux/pci.h > +++ linux-pm/include/linux/pci.h > @@ -344,6 +344,7 @@ struct pci_dev { > D3cold, not set for devices > powered on/off by the > corresponding bridge */ > + unsigned int skip_bus_pm:1; /* Internal: Skip bus-level PM */ > unsigned int ignore_hotplug:1; /* Ignore hotplug events */ > unsigned int hotplug_user_indicators:1; /* SlotCtl indicators > controlled exclusively by >
Bjorn, I've assumed no concerns or objections from you regarding this one and queued it up. If that assumption is incorrect, please let me know.
