From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 299D7C34034 for ; Tue, 18 Feb 2020 04:50:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDC3321D56 for ; Tue, 18 Feb 2020 04:50:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582001414; bh=N+xX+mDsxDGSMkwYZW4RS224VwznzZuqhDmLgQyosBk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=xiwKlqxTLY5EQ+bEZVnXGyHujLUOqyWNy1bMjacMQ4Cd6xMfBy1UrjpIuxsSn3qYz rINT4xgs+oMBoEHuY/W66XEOvvByCuxCTBK7ThvIUZf9ClID0k7z8W/e/Yh9BhFR06 epHXf/vsTTmpXjrhxXKiZyV9HORevMqdhqWtDYNc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726267AbgBREuN (ORCPT ); Mon, 17 Feb 2020 23:50:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:57414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726266AbgBREuN (ORCPT ); Mon, 17 Feb 2020 23:50:13 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7AC9920722; Tue, 18 Feb 2020 04:50:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582001410; bh=N+xX+mDsxDGSMkwYZW4RS224VwznzZuqhDmLgQyosBk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pG4DkmffdTVzSH2OWgrJf+2oB9DEN0h+8C04V3gy8lqGuxE2sQnkXjePHb/uAv+45 4a98ootHMrVVCPi5CCn/XuRfhf3APd4IzhvHA7qxSU635Z6gnyZc1ZlMHeqmBz58DZ /AAvGLSLJ/sQvgZeNvO6ckf6rzv40D8gWkn2NYtI= Date: Tue, 18 Feb 2020 05:50:08 +0100 From: "gregkh@linuxfoundation.org" To: Schrempf Frieder Cc: "u.kleine-koenig@pengutronix.de" , "stable@vger.kernel.org" , "shawnguo@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-serial@vger.kernel.org" Subject: Re: [PATCH 0/2] serial: imx: Backport fixes for irq handling to v4.14 Message-ID: <20200218045008.GA2049358@kroah.com> References: <20200217140740.29743-1-frieder.schrempf@kontron.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200217140740.29743-1-frieder.schrempf@kontron.de> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Feb 17, 2020 at 02:08:00PM +0000, Schrempf Frieder wrote: > From: Frieder Schrempf > > A customer of ours has problems with RS485 on i.MX6UL with the latest v4.14 > kernel. They get an exception like below from time to time (the trace is > from an older kernel, but the problem also exists in v4.14.170). > > As the cpuidle state 2 causes large delays for the interrupt that controls the > RS485 RTS signal (which can lead to collisions on the bus), cpuidle state 2 was > disabled on this system. This aspect might cause the exception happening more > often on this system than on other systems with default cpuidle settings. > > Looking for solutions I found Uwe's patches that were applied in v4.17 being > mentioned here [1] and here [2]. In [1] Uwe notes that backporting these fixes > to v4.14 might not be trivial, but I tried and in my opinion found it not to be > too problematic either. > > With the backported patches applied, our customer reports that the exceptions > stopped occuring. Given this and the fact that the problem seems to be known > and quite common, it would be nice to get this into the v4.14 stable tree. Thanks for the backports, both now queued up. greg k-h