From: Alan Stern <stern@rowland.harvard.edu>
Date: Wed, 18 Apr 2012 15:33:00 +0000 (-0400)
Subject: EHCI: always clear the STS_FLR status bit
X-Git-Tag: v3.0.30~45
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3599fbb407dfa09d1d8d1507961fa03088c3b695;p=karo-tx-linux.git

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 b27ceab17743..6a25c3514097 100644
--- 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;