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@xxxxxxxxxxxxxxxxxxx>
Reported-and-tested-by: Tomoya MORINAGA <tomoya.rohm@xxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
---
This should be applied to 3.4-rc and stable.
drivers/usb/host/ehci-hcd.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
Index: usb-3.4/drivers/usb/host/ehci-hcd.c
===================================================================
--- usb-3.4.orig/drivers/usb/host/ehci-hcd.c
+++ usb-3.4/drivers/usb/host/ehci-hcd.c
@@ -858,8 +858,13 @@ static irqreturn_t ehci_irq (struct usb_
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;
--
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