From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: Re: [PATCH 1/1] can: sja1000: clear interrupts on start Date: Wed, 11 Nov 2015 09:04:53 +0100 Message-ID: <5642F6A5.5070301@pengutronix.de> References: <1447163974-24514-1-git-send-email-mirza.krak@hostmobility.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ULHt5o2hAqNJOUKwPdN0E7TFP1g9p5H2F" Cc: andri.yngvason@marel.com, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Mirza Krak , wg@grandegger.com Return-path: In-Reply-To: <1447163974-24514-1-git-send-email-mirza.krak@hostmobility.com> Sender: linux-can-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --ULHt5o2hAqNJOUKwPdN0E7TFP1g9p5H2F Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 11/10/2015 02:59 PM, Mirza Krak wrote: > From: Mirza Krak >=20 > According to SJA1000 data sheet error-warning (EI) interrupt is not > cleared by setting the controller in to reset-mode. >=20 > Then if we have the following case: > - system is suspended (echo mem > /sys/power/state) and SJA1000 is left= > in operating state This problem occurs only an hardware, where the SJA1000 is powered during system suspend? > - A bus error condition occurs which activates EI interrupt, system is > still suspended which means EI interrupt will be not be handled nor > cleared. >=20 > 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. >=20 > By simply reading the IR register on start we will clear any previous > conditions that could be present. Doesn't the SJA1000 trigger an interrupt that is detected after resuming? You add the fix to the open() function, which is triggered during $(ifconfig up), how is related to suspend/resume? Does the network layer call $(ifconfig down) during shutdown? There isn't any suspend/resume code in the sja1000 driver, for me it seems that we should add resume code that handles this problem. >=20 > Signed-off-by: Mirza Krak > --- > drivers/net/can/sja1000/sja1000.c | 3 +++ > 1 file changed, 3 insertions(+) >=20 > diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja100= 0/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); > =20 > + /* clear interrupt flags */ > + priv->read_reg(priv, SJA1000_IR); > + > /* leave reset mode */ > set_normal_mode(dev); > } >=20 Marc --=20 Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | --ULHt5o2hAqNJOUKwPdN0E7TFP1g9p5H2F Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBCgAGBQJWQvamAAoJEP5prqPJtc/HnmwH/2KKU0NdmoAaGYN4EEgfXPd7 UXQzPVijRO0tYhJ6Yt8j21Zi9kQ+GE2dTw3ax1clLAkJ9R/HjwqZwKSb0/wKk5n5 a7oGDKJkzhRiVCwPf7/LbNakW8XLC6yrrKIn4Svy4+Dj1Ufv02/8wBVHHXPKQ2Zt 1guWmREojZJte6TPR5b7Xw+DzjCkEAjuOwgVPDzpMH8I2BEvcELQrjwipycwUUMI KEWUXvt5GZFGyIYyFegRYrOtNW7ZsCa0xADhiirFKib13PaAllKqGrGC7OcMvso9 cz7J9olfSE16sC8vBHwiZW/vEm5J7px1uywAmwquMICWGrc6GGDQ10aZl+cSStk= =vUt4 -----END PGP SIGNATURE----- --ULHt5o2hAqNJOUKwPdN0E7TFP1g9p5H2F--