From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Stein Subject: Re: exclusive access to can interface Date: Tue, 08 Jan 2013 10:48:58 +0100 Message-ID: <1943558.lxo8ZHFGuj@ws-stein> References: <2412937.XVpYjfC7zz@ws-stein> <2293513.Wi876mfY7y@ws-stein> <50EBE7A9.3050809@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from webbox1416.server-home.net ([77.236.96.61]:50234 "EHLO webbox1416.server-home.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754532Ab3AHJtA (ORCPT ); Tue, 8 Jan 2013 04:49:00 -0500 In-Reply-To: <50EBE7A9.3050809@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: Marc Kleine-Budde Cc: linux-can@vger.kernel.org Hello, On Tuesday 08 January 2013 10:32:25, Marc Kleine-Budde wrote: > On 01/08/2013 10:23 AM, Alexander Stein wrote: > > Hello Marc, > > > > On Monday 07 January 2013 19:16:20, Marc Kleine-Budde wrote: > >> On 01/07/2013 05:52 PM, Alexander Stein wrote: > >>> is there a way to get exclusive (write) access to a CAN interface, so > >>> that only one bound socket can write CAN frames on the bus? > >> > >> No, what's the use case? > > > > This was a customers request in order to prevent multiple applications (or > > instances) to send CAN frames on a specific CAN interface at the same time > > with the very same CAN-IDs. Concurrent reads shall still be allowed! > > Sending CAN frames is proper serialized by the networking subsystem :) > If back to back CAN frames are a problem it seems the design of the > application is fishy. I don't think serializaton or back to back frames are the problem. Think of CANopen there would be the same Node-ID twice on the bus. Alexander