PCI/PM: Do not restore BARs if device is not in D0

Do not attempt to restore the device's BARs in
pci_set_full_power_state() if the actual current
power state of the device is not D0.

Link: https://lore.kernel.org/r/1849718.CQOukoFCf9@kreacher
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 44dcc848ff845abe64afd13f241a8cea55957b08..3320453d2691f75926f8692975bdf8d604844ca6 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1273,25 +1273,25 @@ static int pci_set_full_power_state(struct pci_dev *dev)
 
        pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
        dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK;
-       if (dev->current_state != PCI_D0)
+       if (dev->current_state != PCI_D0) {
                pci_info_ratelimited(dev, "Refused to change power state from %s to D0\n",
                                     pci_power_name(dev->current_state));
-
-       /*
-        * According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
-        * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
-        * from D3hot to D0 _may_ perform an internal reset, thereby
-        * going to "D0 Uninitialized" rather than "D0 Initialized".
-        * For example, at least some versions of the 3c905B and the
-        * 3c556B exhibit this behaviour.
-        *
-        * At least some laptop BIOSen (e.g. the Thinkpad T21) leave
-        * devices in a D3hot state at boot.  Consequently, we need to
-        * restore at least the BARs so that the device will be
-        * accessible to its driver.
-        */
-       if (ret > 0)
+       } else if (ret > 0) {
+               /*
+                * According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
+                * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
+                * from D3hot to D0 _may_ perform an internal reset, thereby
+                * going to "D0 Uninitialized" rather than "D0 Initialized".
+                * For example, at least some versions of the 3c905B and the
+                * 3c556B exhibit this behaviour.
+                *
+                * At least some laptop BIOSen (e.g. the Thinkpad T21) leave
+                * devices in a D3hot state at boot.  Consequently, we need to
+                * restore at least the BARs so that the device will be
+                * accessible to its driver.
+                */
                pci_restore_bars(dev);
+       }
 
        if (dev->bus->self)
                pcie_aspm_pm_state_change(dev->bus->self);