[ 032/167] [PATCH] EHCI: always clear the STS_FLR status bit

Ben Hutchings
2012-05-09T06:28:57Z

From: Alan Stern <stern@rowland.harvard.edu>

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 | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 95ca07a..4a3bc5b 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -858,8 +858,13 @@ 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;
--
1.7.10