From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: [PATCH 1/3] can: sja1000: clear interrupts on start Date: Mon, 23 Nov 2015 09:46:52 +0100 Message-ID: <1448268414-18583-2-git-send-email-mkl@pengutronix.de> References: <1448268414-18583-1-git-send-email-mkl@pengutronix.de> Return-path: In-Reply-To: <1448268414-18583-1-git-send-email-mkl@pengutronix.de> Sender: netdev-owner@vger.kernel.org To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Mirza Krak , linux-stable , Marc Kleine-Budde List-Id: linux-can.vger.kernel.org From: Mirza Krak According to SJA1000 data sheet error-warning (EI) interrupt is not cleared by setting the controller in to reset-mode. Then if we have the following case: - system is suspended (echo mem > /sys/power/state) and SJA1000 is left in operating state - A bus error condition occurs which activates EI interrupt, system is still suspended which means EI interrupt will be not be handled nor cleared. If the above two events occur, on resume there is no way to return the SJA1000 to operating state, except to cycle power to it. By simply reading the IR register on start we will clear any previous conditions that could be present. Signed-off-by: Mirza Krak Reported-by: Christian Magnusson Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/sja1000/sja1000.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c index 7b92e911a616..f10834be48a5 100644 --- a/drivers/net/can/sja1000/sja1000.c +++ b/drivers/net/can/sja1000/sja1000.c @@ -218,6 +218,9 @@ static void sja1000_start(struct net_device *dev) priv->write_reg(priv, SJA1000_RXERR, 0x0); priv->read_reg(priv, SJA1000_ECC); + /* clear interrupt flags */ + priv->read_reg(priv, SJA1000_IR); + /* leave reset mode */ set_normal_mode(dev); } -- 2.6.2