From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Evans Subject: Re: [PATCH 3.19-rc3] c_can: SIE disabled when berr-reporting is off to reduce irq flood Date: Tue, 20 Jan 2015 09:35:56 +1100 Message-ID: <54BD86CC.70302@optusnet.com.au> References: <9c72f211-becc-4c0f-94f6-0700dfb1195e@GRBSR0089.marel.net> <1735533.0yOonAfCy1@heinz> <54B472B2.4010300@optusnet.com.au> <20150113153243.26859.47218@shannon> <54BBFCAF.2090603@pengutronix.de> Reply-To: tom_usenet@optusnet.com.au Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:60058 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751596AbbASWgC (ORCPT ); Mon, 19 Jan 2015 17:36:02 -0500 In-Reply-To: <54BBFCAF.2090603@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: Marc Kleine-Budde , Viktor Babrian , Andri Yngvason Cc: linux-can@vger.kernel.org On 19/01/15 05:34, Marc Kleine-Budde wrote: > On 01/18/2015 07:30 PM, Viktor Babrian wrote: >> >> Status interrupt is to be disabled if bus error reporting is off in order >> to reduce interrupt flood when e.g. a frame is not acked. Side effect is >> that when berr-reporting off, warn->pass and pass-warn state transitions >> may be reported later (upon a successful rx/tx event) or even go >> undetected. With proper implementation, these transitions could always be >> detected (but still later). It is considered better to have a non-accurate >> report of these transitions than having a non-responding system in >> possible scenarios. >> >> Signed-off-by: Viktor Babrian > > NACK. The transitions are important for some applications. I've an not > yet mainlined series that limits the bus errors. I'm going to port them > to the current kernel tomorrow. Can you test it? Those "some applications" can enable "CAN_CTRLMODE_BERR_REPORTING" and get error reporting and prompt (and complete) state reporting. Doesn't that answer your concern? That approach was implemented in flexcan.c as per this patch: > Author: Wolfgang Grandegger 2012-10-11 06:10:42 > Committer: Marc Kleine-Budde 2012-10-24 03:43:17 can: flexcan: disable bus error interrupts for the i.MX6q This patch adds some Flexcan version info and removes the feature flag FLEXCAN_HAS_BROKEN_ERR_STATE for the i.MX6Q. It also has the line [TR]WRN_INT properly connected. You approved this approach then (although possibly not knowing that that was what the patch was doing then). Tom Evans