EHCI: always clear the STS_FLR status bit

commit 2fbe2bf1fd37f9d99950bd8d8093623cf22cf08b upstream.

This patch (as1544) fixes a problem affecting some EHCI controllers.
They can generate interrupts whenever the STS_FLR status bit is turned
on, even though that bit is masked out in the Interrupt Enable
register.

Since the driver doesn't use STS_FLR anyway, the patch changes the
interrupt routine to clear that bit whenever it is set, rather than
leaving it alone.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index b27ceab177438b126cd74e6b41660e59a5823d08..6a25c35140979638b528b7647c9a2f787787668c 100644 (file)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -808,8 +808,13 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
                goto dead;
        }
 
+       /*
+        * We don't use STS_FLR, but some controllers don't like it to
+        * remain on, so mask it out along with the other status bits.
+        */
+       masked_status = status & (INTR_MASK | STS_FLR);
+
        /* Shared IRQ? */
-       masked_status = status & INTR_MASK;
        if (!masked_status || unlikely(hcd->state == HC_STATE_HALT)) {
                spin_unlock(&ehci->lock);
                return IRQ_NONE;