From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: Re: [PATCH v4 7/7] can: add bittiming check at interface open for CAN FD Date: Wed, 26 Feb 2014 21:35:57 +0100 Message-ID: <530E502D.2060601@hartkopp.net> References: <1393009025-4903-1-git-send-email-socketcan@hartkopp.net> <1393009025-4903-8-git-send-email-socketcan@hartkopp.net> <20140226195208.GA10876@vandijck-laurijssen.be> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.218]:40128 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750765AbaBZUgA (ORCPT ); Wed, 26 Feb 2014 15:36:00 -0500 In-Reply-To: <20140226195208.GA10876@vandijck-laurijssen.be> Sender: linux-can-owner@vger.kernel.org List-ID: To: Kurt Van Dijck Cc: linux-can@vger.kernel.org On 26.02.2014 20:52, Kurt Van Dijck wrote: >> + /* For CAN FD the data bitrate has to be >= the arbitration bitrate */ >> + if ((priv->ctrlmode_supported & CAN_CTRLMODE_FD) && >> + (!priv->data_bittiming.tq || !priv->data_bittiming.bitrate || >> + (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) { > > This prevents to configure a data bitrate slower than the arbitration bitrate. > Such configuration is useless, but is it really "incorrect" or wrong? Yes it is. There was a definition that the data bitrate has to be greater or equal the arbitration bitrate. In the Bosch whitepaper about CAN FD Florian Hartwich always states about the higher bitrate - but at least the data bitrate must not be lower than the arbitration bitrate. Regards, Oliver