[PATCH] USB: fix SB600 USB subsystem hang bug

[PATCH] USB: fix SB600 USB subsystem hang bug

[Shane Huang]

This patch is required for all AMD SB600 revisions to avoid USB subsystem hang
symptom. The USB subsystem hang symptom is observed when the system has
multiple USB devices connected to it. In some cases a USB hub may be required
to observe this symptom.

Reported in bugzilla as #11599, the similar patch for SB700 old revision is:
commit b09bc6cbae4dd3a2d35722668ef2c502a7b8b093

Reported-by: raffaele <ralfconn@tele2.it>
Tested-by: Roman Mamedov <roman@rm.pp.ru>
Signed-off-by: Shane Huang <shane.huang@amd.com>

diff -ruN a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
--- a/drivers/usb/host/ehci-pci.c	2008-11-25 18:49:51.000000000 +0800
+++ b/drivers/usb/host/ehci-pci.c	2008-11-25 18:49:55.000000000 +0800
@@ -169,18 +169,21 @@
 		}
 		break;
 	case PCI_VENDOR_ID_ATI:
-		/* SB700 old version has a bug in EHCI controller,
+		/* SB600 and old version of SB700 have a bug in EHCI controller,
 		 * which causes usb devices lose response in some cases.
 		 */
-		if (pdev->device == 0x4396) {
+		if ((pdev->device == 0x4386) || (pdev->device == 0x4396)) {
 			p_smbus = pci_get_device(PCI_VENDOR_ID_ATI,
 						 PCI_DEVICE_ID_ATI_SBX00_SMBUS,
 						 NULL);
 			if (!p_smbus)
 				break;
 			rev = p_smbus->revision;
-			if ((rev == 0x3a) || (rev == 0x3b)) {
+			if ((pdev->device == 0x4386) || (rev == 0x3a)
+			    || (rev == 0x3b)) {
 				u8 tmp;
+				ehci_info(ehci, "applying AMD SB600/SB700 USB "
+					"freeze workaround\n");
 				pci_read_config_byte(pdev, 0x53, &tmp);
 				pci_write_config_byte(pdev, 0x53, tmp | (1<<3));
 			}