From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: Re: pch_can: Data transmission stops after dropped packet Date: Fri, 07 Dec 2012 00:24:02 +0100 Message-ID: <50C12912.7000806@pengutronix.de> References: <50ACABE2.2020306@grandegger.com> <50C0B05F.7020606@grandegger.com> <2331999.ZYFOYXdjyx@ws-stein> <50C1160A.20203@grandegger.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig548FA151ACDDEBDC355B79E3" Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:33841 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753977Ab2LFXYK (ORCPT ); Thu, 6 Dec 2012 18:24:10 -0500 In-Reply-To: <50C1160A.20203@grandegger.com> Sender: linux-can-owner@vger.kernel.org List-ID: To: Wolfgang Grandegger Cc: Alexander Stein , Michael Pellegrini , linux-can@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig548FA151ACDDEBDC355B79E3 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 12/06/2012 11:02 PM, Wolfgang Grandegger wrote: > Hi Michael, >=20 > On 12/06/2012 06:05 PM, Alexander Stein wrote: >> Hi Michael, >>=20 >> On Thursday 06 December 2012 15:49:03, Wolfgang Grandegger wrote: >>>> Details of the soak test: >>>>=20 >>>> There are two systems involved in the test: the PCH-System and >>>> an External Node. The External Node transmits data at a high >>>> rate, bringing bus utilization to ~35%. The PCH-System also >>>> transmits data, in bursts of 10 messages every 5 ms. Combined, >>>> the two systems utilize ~90% of bus bandwidth. The PCH-System >>>> is constantly checking that it is receiving data from the=20 >>>> External Node at the expected rate and in the expected order. >>=20 >> So you do a lot of transmit and reception of CAN frames? >>=20 >>> On another thread Alexander is reporting problems with the same >>> driver when he runs a I2C application concurrently. Are you able >>> to stress the system in a similar way? >>=20 >> Could you please test with the following patch? Do you see error >> messages from this patch? Thanks! >=20 > To summarize my understanding of your problem(s). As long as there > are no I2C transfers, everything works fine, right? The patch below > does report some write-readback failures but that's due to reserved > read-only bits. I assume t hat you also use my "RFC v2" patches for > c_can. >=20 > Trouble starts with concurrent I2C transfers. Then the protected=20 > write-readback test fails, which I regard as abnormal hardware > behavior, resulting in message losses and out-of-order reception. Out-of-sequence reception might be a problem due to a problem in the rx algorithm. And the drops are probably due to overflowing rx mailboxes. The out-of-sequence will most mist likely occur if the rx fifo runs full, but does not overflow. 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 | --------------enig548FA151ACDDEBDC355B79E3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlDBKRYACgkQjTAFq1RaXHOV1ACgk0DSTNi8AZ46ZANMMvfJfTuJ GawAnRstYWtFBvtWfPsUH2flQrmtcboU =H/CC -----END PGP SIGNATURE----- --------------enig548FA151ACDDEBDC355B79E3--