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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 A848AC43381 for ; Fri, 22 Feb 2019 10:30:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 249052081B for ; Fri, 22 Feb 2019 10:30:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726766AbfBVKaZ (ORCPT ); Fri, 22 Feb 2019 05:30:25 -0500 Received: from mx0a-001ae601.pphosted.com ([67.231.149.25]:42016 "EHLO mx0b-001ae601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725906AbfBVKaZ (ORCPT ); Fri, 22 Feb 2019 05:30:25 -0500 Received: from pps.filterd (m0077473.ppops.net [127.0.0.1]) by mx0a-001ae601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1MATN3Z024332; Fri, 22 Feb 2019 04:30:20 -0600 Authentication-Results: ppops.net; spf=none smtp.mailfrom=ckeepax@opensource.cirrus.com Received: from mail4.cirrus.com ([87.246.98.35]) by mx0a-001ae601.pphosted.com with ESMTP id 2qpgt5tjch-1; Fri, 22 Feb 2019 04:30:20 -0600 Received: from EX17.ad.cirrus.com (unknown [172.20.9.81]) by mail4.cirrus.com (Postfix) with ESMTP id B3907611C8AF; Fri, 22 Feb 2019 04:30:58 -0600 (CST) Received: from imbe.wolfsonmicro.main (198.61.95.81) by EX17.ad.cirrus.com (172.20.9.81) with Microsoft SMTP Server id 14.3.408.0; Fri, 22 Feb 2019 10:30:19 +0000 Received: from ediswmail.ad.cirrus.com (ediswmail.ad.cirrus.com [198.61.86.93]) by imbe.wolfsonmicro.main (8.14.4/8.14.4) with ESMTP id x1MAUJwY019509; Fri, 22 Feb 2019 10:30:19 GMT Date: Fri, 22 Feb 2019 10:30:19 +0000 From: Charles Keepax To: Wolfram Sang CC: Benjamin Tissoires , Jim Broadus , Linux I2C , lkml Subject: Re: [PATCH] i2c: Allow recovery of the initial IRQ by an I2C client device. Message-ID: <20190222103019.GD130153@ediswmail.ad.cirrus.com> References: <20190219193027.13882-1-jbroadus@gmail.com> <20190221232609.d4vxl3osj6mwooey@katana> <20190222102335.GA1771@kunai> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20190222102335.GA1771@kunai> User-Agent: Mutt/1.5.21 (2010-09-15) X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902220074 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 22, 2019 at 11:23:35AM +0100, Wolfram Sang wrote: > On Fri, Feb 22, 2019 at 11:15:59AM +0100, Benjamin Tissoires wrote: > > On Fri, Feb 22, 2019 at 12:26 AM Wolfram Sang wrote: > > > On Tue, Feb 19, 2019 at 11:30:27AM -0800, Jim Broadus wrote: > > > > A previous change allowed I2C client devices to discover new IRQs upon > > > > reprobe by clearing the IRQ in i2c_device_remove. However, if an IRQ was > > > > assigned in i2c_new_device, that information is lost. > > > > > > > > For example, the touchscreen and trackpad devices on a Dell Inspiron laptop > > > > are I2C devices whose IRQs are defined by ACPI extended IRQ types. The > > > > client device structures are initialized during an ACPI walk. After > > > > removing the i2c_hid device, modprobe fails. > > > > > > > > This change caches the initial IRQ value in i2c_new_device and then resets > > > > the client device IRQ to the initial value in i2c_device_remove. > > > > > > > > Fixes: 6f108dd70d30 ("i2c: Clear client->irq in i2c_device_remove") > > > > Signed-off-by: Jim Broadus > > > > > > Adding Benjamin to CC > > > > Sorry, I should have answered earlier. > > > > I am a little bit hesitant regarding this patch. The effect is > > correct, and I indeed realized a few weeks ago that something were > > wrong as we couldn't rmmod/modprobe i2c-hid. > > > > But I still have the feeling that the problem is not solved at the > > right place. In i2c_new_device() we are storing parts of the fields of > > struct i2c_board_info, and when resetting the irq we are losing > > information. This patch solves that, but I wonder if the IRQ should > > not be 'simply' set in i2c_device_probe(). This means we also need to > > store the .resources of info, but I have a feeling this will be less > > error prone in the future. > > > > But this is just my guts telling me something is not right. I would > > perfectly understand if we want to get this merged ASAP. > > > > So given that the code is correct, this is my: > > Reviewed-by: Benjamin Tissoires > > > > But at least I have expressed my feelings :) > > Which I can relate to very much. I see the code solves the issue but my > feeling is that we are patching around something which should be handled > differently in general. > > Is somebody willing to research this further? > > Thanks for your input. > I would be willing to have more of a look at it but am slightly nervous I am not right person as all the systems I currently work with are DT based so don't really exemplify the issue at all. Thanks, Charles