[PATCH AUTOSEL 4.19 20/49] ACPI/PCI: PM: Add missing wakeup.flags.valid checks

[PATCH AUTOSEL 4.19 20/49] ACPI/PCI: PM: Add missing wakeup.flags.valid checks

[Sasha Levin]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

[ Upstream commit 9a51c6b1f9e0239a9435db036b212498a2a3b75c ]

Both acpi_pci_need_resume() and acpi_dev_needs_resume() check if the
current ACPI wakeup configuration of the device matches what is
expected as far as system wakeup from sleep states is concerned, as
reflected by the device_may_wakeup() return value for the device.

However, they only should do that if wakeup.flags.valid is set for
the device's ACPI companion, because otherwise the wakeup.prepare_count
value for it is meaningless.

Add the missing wakeup.flags.valid checks to these functions.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/device_pm.c | 4 ++--
 drivers/pci/pci-acpi.c   | 3 ++-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index a7c2673ffd36..1806260938e8 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -948,8 +948,8 @@ static bool acpi_dev_needs_resume(struct device *dev, struct acpi_device *adev)
 	u32 sys_target = acpi_target_system_state();
 	int ret, state;
 
-	if (!pm_runtime_suspended(dev) || !adev ||
-	    device_may_wakeup(dev) != !!adev->wakeup.prepare_count)
+	if (!pm_runtime_suspended(dev) || !adev || (adev->wakeup.flags.valid &&
+	    device_may_wakeup(dev) != !!adev->wakeup.prepare_count))
 		return true;
 
 	if (sys_target == ACPI_STATE_S0)
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index f8436d1c4d45..f7218c1673ce 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -625,7 +625,8 @@ static bool acpi_pci_need_resume(struct pci_dev *dev)
 	if (!adev || !acpi_device_power_manageable(adev))
 		return false;
 
-	if (device_may_wakeup(&dev->dev) != !!adev->wakeup.prepare_count)
+	if (adev->wakeup.flags.valid &&
+	    device_may_wakeup(&dev->dev) != !!adev->wakeup.prepare_count)
 		return true;
 
 	if (acpi_target_system_state() == ACPI_STATE_S0)
-- 
2.20.1

[PATCH AUTOSEL 4.19 21/49] PCI: PM: Avoid possible suspend-to-idle issue

[Sasha Levin]

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 33f3f475e5c6..7430f993567f 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -734,6 +734,8 @@ 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);
 
@@ -827,7 +829,20 @@ 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 b1f297f4b7b0..94853094b6ef 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -342,6 +342,7 @@ 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
-- 
2.20.1