From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Altenberg" Subject: Re: can: c_can: TX delivery Date: Wed, 23 Mar 2011 16:32:31 +0100 Message-ID: References: <16a340801622a96218c76dbbabc7a23f.squirrel@www.linutronix.de> <20110323085340.GC346@e-circ.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: "Jan Altenberg" , bhupesh.sharma@st.com, wg@grandegger.com, b.spranger@linutronix.de, netdev@vger.kernel.org To: "Kurt Van Dijck" Return-path: Received: from www.linutronix.de ([62.245.132.108]:48443 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933043Ab1CWPcf (ORCPT ); Wed, 23 Mar 2011 11:32:35 -0400 In-Reply-To: <20110323085340.GC346@e-circ.dyndns.org> Sender: netdev-owner@vger.kernel.org List-ID: Hi, > I split your 2 questions in 2 replies. Thanks :) > not sure if I made my point. Note that this will eliminate the need > for explicit wrap-around. It's done implicitely. Hmmm, I double-checked the datasheet, which gives the following statement: "The receive/transmit priority for the Message Objects is attached to the message number. Message Object 1 has the highest priority, while Message Object 32 has the lowest priority. If more than one transmission request is pending, they are serviced due to the priority of the corresponding Message Object." So, we shouldn't run into the scenario I described in my previous mail and the existing implementation should be OK, right?! I'm quite sure I've seen a situation where msg_obj 17 "seemed" to be pending, while msg_obj 18 and 19 already have been transmitted. But in that case, I enabled ONESHOT for the can interface, which enables the DA mode (automatic retransmission is disabled). The errata sheet for c_can covers that mode. There's a problem with "Concurrent transmission requests" and I'm quite sure my test-case hit that problem. I'm quite new to Bosch's c_can, so maybe Bhupesh can give some feedback (or beat me for causing some confusion ;-)). Sorry for the confusion! Jan