[PATCH 4.9 10/21] PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()

From: Greg Kroah-Hartman
Date: Wed Dec 27 2017 - 11:46:51 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

commit 5839ee7389e893a31e4e3c9cf17b50d14103c902 upstream.

It is incorrect to call pci_restore_state() for devices in low-power
states (D1-D3), as that involves the restoration of MSI setup which
requires MMIO to be operational and that is only the case in D0.

However, pci_pm_thaw_noirq() may do that if the driver's "freeze"
callbacks put the device into a low-power state, so fix it by making
it force devices into D0 via pci_set_power_state() instead of trying
to "update" their power state which is pointless.

Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation)
Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reported-by: Maarten Lankhorst <dev@xxxxxxxxxxxxxx>
Tested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Maarten Lankhorst <dev@xxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/pci/pci-driver.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -953,7 +953,12 @@ static int pci_pm_thaw_noirq(struct devi
if (pci_has_legacy_pm_support(pci_dev))
return pci_legacy_resume_early(dev);

- pci_update_current_state(pci_dev, PCI_D0);
+ /*
+ * pci_restore_state() requires the device to be in D0 (because of MSI
+ * restoration among other things), so force it into D0 in case the
+ * driver's "freeze" callbacks put it into a low-power state directly.
+ */
+ pci_set_power_state(pci_dev, PCI_D0);

if (drv && drv->pm && drv->pm->thaw_noirq)