Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[deliverable/linux.git] / drivers / pci / pci-driver.c

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index bf0cee629b60f8bb763b4407f631e7ba7e778aa8..099f46cd8e87a4ca823dc24f707458857f26eaa5 100644 (file)
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -748,6 +748,18 @@ 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;
 }