[PATCH] x445 usb legacy fix

[john stultz <johnstul@us.ibm.com>]

Greg, All,
	Apparently there is an issue w/ the IBM x440/x445's BIOS's USB Legacy
support. Due to the delay in issuing SMI's across the IOAPICs, its
possible for I/O to ports 60/64 to cause register corruption. 

The solution is to disable the BIOS's USB Legacy support early in boot
(via PCI quirks) for x440/x445 systems. 

This is the same method posted to lkml here (Originally written by
Vojtech): http://www.ussg.iu.edu/hypermail/linux/kernel/0405.3/1712.html

(Use the following link for the raw mbox email)
http://lkml.org/lkml/mbox/2004/5/31/97

While Greg was cautious that this method couldn't always be used, I've
created a patch that applies on top of Vojtech's that creates a boot
option which allows you to specify "no-usb-legacy". Additionally this
patch enables the "no-usb-legacy" option by default for x440/x445
systems.

Please consider for inclusion (along with the patch linked to above)
into your tree. 

thanks
-john

diff -Nru a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
--- a/Documentation/kernel-parameters.txt	Mon Jul 19 18:06:40 2004
+++ b/Documentation/kernel-parameters.txt	Mon Jul 19 18:06:40 2004
@@ -757,6 +757,8 @@
 
 	nousb		[USB] Disable the USB subsystem
 
+	no-usb-legacy	[USB] Disables BIOS SMM USB Legacy Support
+
 	nowb		[ARM]
  
 	opl3=		[HW,OSS]
diff -Nru a/drivers/pci/quirks.c b/drivers/pci/quirks.c
--- a/drivers/pci/quirks.c	Mon Jul 19 18:06:40 2004
+++ b/drivers/pci/quirks.c	Mon Jul 19 18:06:40 2004
@@ -916,8 +916,18 @@
 #define OHCI_CTRL_IR		(1 << 8)	/* interrupt routing */
 #define OHCI_INTR_OC		(1 << 30)	/* ownership change */
 
+int disable_legacy_usb __initdata = 0;
+static int __init usb_legacy_disable(char *str)
+{
+	disable_legacy_usb = 1;
+	return 0;
+}
+__setup("no-usb-legacy", usb_legacy_disable);
+
 static void __init quirk_usb_disable_smm_bios(struct pci_dev *pdev)
 {
+	if (!disable_legacy_usb)
+		return;
 
 	if (pdev->class == ((PCI_CLASS_SERIAL_USB << 8) | 0x00)) { /* UHCI */
 		int i;
diff -Nru a/include/asm-i386/mach-summit/mach_mpparse.h b/include/asm-i386/mach-summit/mach_mpparse.h
--- a/include/asm-i386/mach-summit/mach_mpparse.h	Mon Jul 19 18:06:40 2004
+++ b/include/asm-i386/mach-summit/mach_mpparse.h	Mon Jul 19 18:06:40 2004
@@ -22,6 +22,7 @@
 {
 }
 
+extern int disable_legacy_usb;
 static inline int mps_oem_check(struct mp_config_table *mpc, char *oem, 
 		char *productid)
 {
@@ -31,6 +32,7 @@
 			 || !strncmp(productid, "RUTHLESS SMP", 12))){
 		use_cyclone = 1; /*enable cyclone-timer*/
 		setup_summit();
+		disable_legacy_usb = 1;
 		return 1;
 	}
 	return 0;
@@ -44,6 +46,7 @@
 	     || !strncmp(oem_table_id, "EXA", 3))){
 		use_cyclone = 1; /*enable cyclone-timer*/
 		setup_summit();
+		disable_legacy_usb = 1;
 		return 1;
 	}
 	return 0;