PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()

[pandora-kernel.git] / drivers / pci / pci-driver.c

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 12d1e81..5dde000 100644 (file)
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -742,6 +742,18 @@ static int pci_pm_suspend_noirq(struct device *dev)
 
        pci_pm_set_unknown_state(pci_dev);
 
+       /*
+        * Some BIOSes from ASUS have a bug: If a USB EHCI host controller's
+        * PCI COMMAND register isn't 0, the BIOS assumes that the controller
+        * hasn't been quiesced and tries to turn it off.  If the controller
+        * is already in D3, this can hang or cause memory corruption.
+        *
+        * Since the value of the COMMAND register doesn't matter once the
+        * device has been suspended, we can safely set it to 0 here.
+        */
+       if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
+               pci_write_config_word(pci_dev, PCI_COMMAND, 0);
+
        return 0;
 }
 
@@ -860,7 +872,13 @@ 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)
                error = drv->pm->thaw_noirq(dev);
@@ -940,6 +958,13 @@ static int pci_pm_poweroff_noirq(struct device *dev)
        if (!pci_dev->state_saved && !pci_is_bridge(pci_dev))
                pci_prepare_to_sleep(pci_dev);
 
+       /*
+        * The reason for doing this here is the same as for the analogous code
+        * in pci_pm_suspend_noirq().
+        */
+       if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
+               pci_write_config_word(pci_dev, PCI_COMMAND, 0);
+
        return 0;
 }