[PATCH 4.9 45/67] can: cc770: Fix stalls on rt-linux, remove redundant IRQ ack

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andri Yngvason <andri.yngvason@xxxxxxxxx>

commit f4353daf4905c0099fd25fa742e2ffd4a4bab26a upstream.

This has been reported to cause stalls on rt-linux.

Suggested-by: Richard Weinberger <richard@xxxxxx>
Tested-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Andri Yngvason <andri.yngvason@xxxxxxxxx>
Cc: linux-stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/can/cc770/cc770.c |   15 ---------------
 1 file changed, 15 deletions(-)

--- a/drivers/net/can/cc770/cc770.c
+++ b/drivers/net/can/cc770/cc770.c
@@ -447,15 +447,6 @@ static netdev_tx_t cc770_start_xmit(stru
 
 	stats->tx_bytes += dlc;
 
-
-	/*
-	 * HM: We had some cases of repeated IRQs so make sure the
-	 * INT is acknowledged I know it's already further up, but
-	 * doing again fixed the issue
-	 */
-	cc770_write_reg(priv, msgobj[mo].ctrl0,
-			MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES);
-
 	return NETDEV_TX_OK;
 }
 
@@ -684,12 +675,6 @@ static void cc770_tx_interrupt(struct ne
 	/* Nothing more to send, switch off interrupts */
 	cc770_write_reg(priv, msgobj[mo].ctrl0,
 			MSGVAL_RES | TXIE_RES | RXIE_RES | INTPND_RES);
-	/*
-	 * We had some cases of repeated IRQ so make sure the
-	 * INT is acknowledged
-	 */
-	cc770_write_reg(priv, msgobj[mo].ctrl0,
-			MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES);
 
 	stats->tx_packets++;
 	can_get_echo_skb(dev, 0);