[patch 40/46] USB: EHCI: fix handling of dead controllers

[Greg KH]

2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

commit 67b2e029743a52670d77864723b4d0d40f7733b5 upstream.

This patch (as1165) makes a few small changes in the logic used by
ehci-hcd when it encounters a controller error:

	Instead of printing out the masked status, it prints the
	original status as read directly from the hardware.

	It doesn't check for the STS_HALT status bit before taking
	action.  The mere fact that the STS_FATAL bit is set means
	that something bad has happened and the controller needs to
	be reset.  With the old code this test could never succeed
	because the STS_HALT bit was masked out from the status.

I anticipate that this will prevent the occasional "irq X: nobody cared"
problem people encounter when their EHCI controllers die.

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/usb/host/ehci-hcd.c |   25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -643,7 +643,7 @@ static int ehci_run (struct usb_hcd *hcd
 static irqreturn_t ehci_irq (struct usb_hcd *hcd)
 {
 	struct ehci_hcd		*ehci = hcd_to_ehci (hcd);
-	u32			status, pcd_status = 0, cmd;
+	u32			status, masked_status, pcd_status = 0, cmd;
 	int			bh;
 
 	spin_lock (&ehci->lock);
@@ -656,14 +656,14 @@ static irqreturn_t ehci_irq (struct usb_
 		goto dead;
 	}
 
-	status &= INTR_MASK;
-	if (!status) {			/* irq sharing? */
+	masked_status = status & INTR_MASK;
+	if (!masked_status) {		/* irq sharing? */
 		spin_unlock(&ehci->lock);
 		return IRQ_NONE;
 	}
 
 	/* clear (just) interrupts */
-	ehci_writel(ehci, status, &ehci->regs->status);
+	ehci_writel(ehci, masked_status, &ehci->regs->status);
 	cmd = ehci_readl(ehci, &ehci->regs->command);
 	bh = 0;
 
@@ -731,19 +731,18 @@ static irqreturn_t ehci_irq (struct usb_
 
 	/* PCI errors [4.15.2.4] */
 	if (unlikely ((status & STS_FATAL) != 0)) {
+		ehci_err(ehci, "fatal error\n");
 		dbg_cmd (ehci, "fatal", ehci_readl(ehci,
 						   &ehci->regs->command));
 		dbg_status (ehci, "fatal", status);
-		if (status & STS_HALT) {
-			ehci_err (ehci, "fatal error\n");
+		ehci_halt(ehci);
 dead:
-			ehci_reset (ehci);
-			ehci_writel(ehci, 0, &ehci->regs->configured_flag);
-			/* generic layer kills/unlinks all urbs, then
-			 * uses ehci_stop to clean up the rest
-			 */
-			bh = 1;
-		}
+		ehci_reset(ehci);
+		ehci_writel(ehci, 0, &ehci->regs->configured_flag);
+		/* generic layer kills/unlinks all urbs, then
+		 * uses ehci_stop to clean up the rest
+		 */
+		bh = 1;
 	}
 
 	if (bh)

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