From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Stein Subject: Re: [PATCH 4/4] can: flexcan: Disable error irq when in error passive Date: Thu, 14 Aug 2014 15:19:37 +0200 Message-ID: <2700138.iRYuM1TADC@ws-stein> References: <1407850987-26707-1-git-send-email-alexander.stein@systec-electronic.com> <1407850987-26707-4-git-send-email-alexander.stein@systec-electronic.com> <53EC9B17.80600@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]:39432 "EHLO webbox1416.server-home.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754297AbaHNNXF (ORCPT ); Thu, 14 Aug 2014 09:23:05 -0400 In-Reply-To: <53EC9B17.80600@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: Marc Kleine-Budde Cc: Wolfgang Grandegger , linux-can@vger.kernel.org On Thursday 14 August 2014 13:18:47, Marc Kleine-Budde wrote: > On 08/12/2014 03:43 PM, Alexander Stein wrote: > > If the error irq is enabled and the hardware is trying to send a CAN > > message to an open bus it will receive a lot of acknowledge errors and > > generating lots of interrupts. So error interrupts are disabled when > > entering error passive and reenable them when leaving error passive. > > We can only leave error passive by receiving CAN frames in which case NAPI > > is scheduled anyway or by sending more CAN frames when send is possible > > again. But with the transition of error counters from 96 to 95 the flags > > TX_WRN and RX_WRN are gone again, so we need to remember the flags state > > to detect a change there. > > There are use cases where the error interrupts even when in passive mode > are essential. You have a use case, where you'd like to turn them off > completely. Have you had a look at the bus error limiting patches? Do you mean "[PATCH v7] flexcan: add err_irq handler for flexcan" from Zhao Qiang? Best regards, Alexander -- Dipl.-Inf. Alexander Stein SYS TEC electronic GmbH Am Windrad 2 08468 Heinsdorfergrund Tel.: 03765 38600-1156 Fax: 03765 38600-4100 Email: alexander.stein@systec-electronic.com Website: www.systec-electronic.com Managing Director: Dipl.-Phys. Siegmar Schmidt Commercial registry: Amtsgericht Chemnitz, HRB 28082