PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()
authorRafael J. Wysocki <rafael.j.wysocki@intel.com>
Fri, 15 Dec 2017 02:07:18 +0000 (03:07 +0100)
committerBen Hutchings <ben@decadent.org.uk>
Sat, 3 Mar 2018 15:50:48 +0000 (15:50 +0000)
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@linutronix.de>
Reported-by: Maarten Lankhorst <dev@mblankhorst.nl>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Maarten Lankhorst <dev@mblankhorst.nl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
drivers/pci/pci-driver.c

index fa63507..5dde000 100644 (file)
@@ -872,7 +872,12 @@ static int pci_pm_thaw_noirq(struct device *dev)
        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);
        pci_restore_state(pci_dev);
 
        if (drv && drv->pm && drv->pm->thaw_noirq)