ehci-hcd: Disable memory-write-invalidate when the driver is removed

The driver calls pci_set_mwi to enable memory-write-invalidate when it
is initialized, but does not call pci_clear_mwi when it is removed. Many
other drivers calls pci_clear_mwi when pci_set_mwi is called, such as
r8169, 8139cp and e1000.

This patch adds a function "ehci_pci_remove" to remove the pci driver.
This function calls pci_clear_mwi and usb_hcd_pci_remove, which can
fix the problem.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-pci.c

@@ -377,6 +377,12 @@ static int ehci_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	return usb_hcd_pci_probe(pdev, id);
 }
 
+static void ehci_pci_remove(struct pci_dev *pdev)
+{
+	pci_clear_mwi(pdev);
+	usb_hcd_pci_remove(pdev);	
+}
+
 /* PCI driver selection metadata; PCI hotplugging uses this */
 static const struct pci_device_id pci_ids [] = { {
 	/* handle any USB 2.0 EHCI controller */
@@ -396,7 +402,7 @@ static struct pci_driver ehci_pci_driver = {
 	.id_table =	pci_ids,
 
 	.probe =	ehci_pci_probe,
-	.remove =	usb_hcd_pci_remove,
+	.remove =	ehci_pci_remove,
 	.shutdown = 	usb_hcd_pci_shutdown,
 
 #ifdef CONFIG_PM