On Tue, Jun 11, 2019 at 05:25:48PM +0200, Rafael J. Wysocki wrote:
On 6/8/2019 1:46 PM, Sasha Levin wrote:
From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com
[ Upstream commit d491f2b75237ef37d8867830ab7fad8d9659e853 ]
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 rafael.j.wysocki@intel.com Reviewed-by: Keith Busch keith.busch@intel.com Reviewed-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org
drivers/pci/pci-driver.c | 17 ++++++++++++++++- include/linux/pci.h | 1 + 2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index ea69b4dbab66..f5d66335fe53 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -726,6 +726,8 @@ static int pci_pm_suspend(struct device *dev) 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);
@@ -799,7 +801,20 @@ static int pci_pm_suspend_noirq(struct device *dev) } }
- 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);
diff --git a/include/linux/pci.h b/include/linux/pci.h index 59f4d10568c6..430f3c335446 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -346,6 +346,7 @@ 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
This has been reported to be problematic, I wouldn't recommend taking it for -stable at this point.
I've dropped it, thank you.
-- Thanks, Sasha