EHCI: always clear the STS_FLR status bit
authorAlan Stern <stern@rowland.harvard.edu>
Wed, 18 Apr 2012 15:33:00 +0000 (11:33 -0400)
committerBen Hutchings <ben@decadent.org.uk>
Fri, 11 May 2012 12:14:02 +0000 (13:14 +0100)
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
drivers/usb/host/ehci-hcd.c

index ffbbf54..da2f711 100644 (file)
@@ -815,8 +815,13 @@ 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(ehci->rh_state == EHCI_RH_HALTED)) {
                spin_unlock(&ehci->lock);
                return IRQ_NONE;