Patch "xhci: Fix register save/restore order." has been added to the 3.0-stable tree

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This is a note to let you know that I've just added the patch titled

    xhci: Fix register save/restore order.

to the 3.0-stable tree which can be found at:;a=summary

The filename of the patch is:
and it can be found in the queue-3.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.

>From c7713e736526d8c9f6f87716fb90562a8ffaff2c Mon Sep 17 00:00:00 2001
From: Sarah Sharp <>
Date: Fri, 16 Mar 2012 13:19:35 -0700
Subject: xhci: Fix register save/restore order.

From: Sarah Sharp <>

commit c7713e736526d8c9f6f87716fb90562a8ffaff2c upstream.

The xHCI 1.0 spec errata released on June 13, 2011, changes the ordering
that the xHCI registers are saved and restored in.  It moves the
interrupt pending (IMAN) and interrupt control (IMOD) registers to be
saved and restored last.  I believe that's because the host controller
may attempt to fetch the event ring table when interrupts are
re-enabled.  Therefore we need to restore the event ring registers
before we re-enable interrupts.

This should be backported to kernels as old as 2.6.37, that contain the
commit 5535b1d5f8885695c6ded783c692e3c0d0eda8ca "USB: xHCI: PCI power
management implementation"

Signed-off-by: Sarah Sharp <>
Tested-by: Elric Fu <elricfu1@xxxxxxxxx>
Cc: Andiry Xu <andiry.xu@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

 drivers/usb/host/xhci.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -610,11 +610,11 @@ static void xhci_save_registers(struct x
 	xhci->s3.dev_nt = xhci_readl(xhci, &xhci->op_regs->dev_notification);
 	xhci->s3.dcbaa_ptr = xhci_read_64(xhci, &xhci->op_regs->dcbaa_ptr);
 	xhci->s3.config_reg = xhci_readl(xhci, &xhci->op_regs->config_reg);
-	xhci->s3.irq_pending = xhci_readl(xhci, &xhci->ir_set->irq_pending);
-	xhci->s3.irq_control = xhci_readl(xhci, &xhci->ir_set->irq_control);
 	xhci->s3.erst_size = xhci_readl(xhci, &xhci->ir_set->erst_size);
 	xhci->s3.erst_base = xhci_read_64(xhci, &xhci->ir_set->erst_base);
 	xhci->s3.erst_dequeue = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
+	xhci->s3.irq_pending = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+	xhci->s3.irq_control = xhci_readl(xhci, &xhci->ir_set->irq_control);
 static void xhci_restore_registers(struct xhci_hcd *xhci)
@@ -623,11 +623,11 @@ static void xhci_restore_registers(struc
 	xhci_writel(xhci, xhci->s3.dev_nt, &xhci->op_regs->dev_notification);
 	xhci_write_64(xhci, xhci->s3.dcbaa_ptr, &xhci->op_regs->dcbaa_ptr);
 	xhci_writel(xhci, xhci->s3.config_reg, &xhci->op_regs->config_reg);
-	xhci_writel(xhci, xhci->s3.irq_pending, &xhci->ir_set->irq_pending);
-	xhci_writel(xhci, xhci->s3.irq_control, &xhci->ir_set->irq_control);
 	xhci_writel(xhci, xhci->s3.erst_size, &xhci->ir_set->erst_size);
 	xhci_write_64(xhci, xhci->s3.erst_base, &xhci->ir_set->erst_base);
 	xhci_write_64(xhci, xhci->s3.erst_dequeue, &xhci->ir_set->erst_dequeue);
+	xhci_writel(xhci, xhci->s3.irq_pending, &xhci->ir_set->irq_pending);
+	xhci_writel(xhci, xhci->s3.irq_control, &xhci->ir_set->irq_control);
 static void xhci_set_cmd_ring_deq(struct xhci_hcd *xhci)

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