From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: Re: [PATCH V3 3/3] can: m_can: workaround for transmit data less than 4 bytes Date: Wed, 05 Nov 2014 15:29:37 +0100 Message-ID: <545A3451.2090302@pengutronix.de> References: <1415193393-30023-1-git-send-email-b29396@freescale.com> <1415193393-30023-3-git-send-email-b29396@freescale.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="30LlXH8aOD0Wqm92JB6ehnQGhBM1l2PNK" Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:39868 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753888AbaKEO3r (ORCPT ); Wed, 5 Nov 2014 09:29:47 -0500 In-Reply-To: <1415193393-30023-3-git-send-email-b29396@freescale.com> Sender: linux-can-owner@vger.kernel.org List-ID: To: Dong Aisheng , linux-can@vger.kernel.org Cc: wg@grandegger.com, varkabhadram@gmail.com, netdev@vger.kernel.org, socketcan@hartkopp.net, linux-arm-kernel@lists.infradead.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --30LlXH8aOD0Wqm92JB6ehnQGhBM1l2PNK Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 11/05/2014 02:16 PM, Dong Aisheng wrote: > At least on the i.MX6SX TO1.2 with M_CAN IP version 3.0.1, an issue wit= h > the Message RAM was discovered. Sending CAN frames with dlc less > than 4 bytes will lead to bit errors, when the first 8 bytes of > the Message RAM have not been initialized (i.e. written to). > To work around this issue, the first 8 bytes are initialized in open() > function. >=20 > Without the workaround, we can easily see the following errors: > root@imx6qdlsolo:~# ip link set can0 up type can bitrate 1000000 > [ 66.882520] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready > root@imx6qdlsolo:~# cansend can0 123#112233 > [ 66.935640] m_can 20e8000.can can0: Bit Error Uncorrected >=20 > Signed-off-by: Dong Aisheng Applied to can/master Thanks, 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 | --30LlXH8aOD0Wqm92JB6ehnQGhBM1l2PNK 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 iQIcBAEBAgAGBQJUWjRRAAoJECte4hHFiupUDHAQAJ+4ZJ4klnGUhHyvmRy32kWJ Mdds7ZOJXVJ7YWHJwysnumMibLwgOJhIXw890KTlz1nHMQeR3rstiaPvqOEuJTrv kw+uZ1rAQNeMBH38w7Ltk+8w5F9hT6ns9cMNHPuW5UjiY0zIBoBbgaCJNmSfHeD2 tB9P9fhvui5ED6hTRqQOUplqJQYP2NbTe0RIBuMJQapV45H//L8WCVyw52doEnNA 0fWb62a7vy+7H4xEgOVJVyTXsACYIHv0tNq4b2vtI5zPOlxUE/00eODxuWJgm7H5 A+7sHDuiUTQ8df+sdOCf/JteyBuh0Ee0iLiiNF/3WX+xX4ABaiTHzGtQwFCIYeTf fudr5Ng/aNoWvNNQaU6M7lXdtJSnDDrUqUszFRftNO+8G9/KXLeVWX8OhSjhYr5b K7xd0+MV5uWKv55o+yN/AxG0mQxvuiZOZ08BYQrfQBWL8G0nP+Kuv68Kpu2fyAkX NEHLPXDScN5WEXj0yTZ7whHMRSdRvGYaaKfEWEyiT4q6TMwWLI934Tnfq8XEVDW/ tY1YLSLGWYDuHpnh3WZ7KMJu1nHLKncKoc//vLyftjGcmJBej+ISQqZPHif6WtSF LdSPp3pqc90k0VbZ+jB85OzqI/7aI6m1a4rQ2xb1kv0IXcKsGcjY6uH0vA3ACiMp s/+AZ8ukvWMgGgnEASsd =XgR+ -----END PGP SIGNATURE----- --30LlXH8aOD0Wqm92JB6ehnQGhBM1l2PNK--