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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED 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 62FBCC2D0E5 for ; Fri, 27 Mar 2020 22:25:48 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1B6042073B for ; Fri, 27 Mar 2020 22:25:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B6042073B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id C32838867E; Fri, 27 Mar 2020 22:25:47 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id hiO7Vzx+0T0O; Fri, 27 Mar 2020 22:25:44 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 10B2E88673; Fri, 27 Mar 2020 22:25:44 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id DB3CDC1D8A; Fri, 27 Mar 2020 22:25:43 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 53219C0177 for ; Fri, 27 Mar 2020 22:25:41 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 4236E20478 for ; Fri, 27 Mar 2020 22:25:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id J6RqUL4oLzeG for ; Fri, 27 Mar 2020 22:25:40 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by silver.osuosl.org (Postfix) with ESMTPS id 08C112107D for ; Fri, 27 Mar 2020 22:25:40 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id A3857296825 Message-ID: <761b5165f6708bb707148cfdee13d9b710eef29c.camel@collabora.com> Subject: Re: [PATCH] iommu: Lower severity of add/remove device messages From: Ezequiel Garcia To: Robin Murphy , Joerg Roedel Date: Fri, 27 Mar 2020 19:25:27 -0300 In-Reply-To: <6db3bcfb-c778-7190-a936-836eaba4bb73@arm.com> References: <20200323214956.30165-1-ezequiel@collabora.com> <20200327095029.GB11538@8bytes.org> <9e863f96cd9a188db84ae8bc5a0d49287b4b4922.camel@collabora.com> <6db3bcfb-c778-7190-a936-836eaba4bb73@arm.com> Organization: Collabora User-Agent: Evolution 3.36.0-1 MIME-Version: 1.0 Cc: iommu@lists.linux-foundation.org, kernel@collabora.com, linux-kernel@vger.kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Fri, 2020-03-27 at 18:04 +0000, Robin Murphy wrote: > On 2020-03-27 1:02 pm, Ezequiel Garcia wrote: > > Hello Joerg, > > > > Thanks for reviewing. > > > > I understand this change bears some controversy > > for IOMMU, as developers are probably used to see these > > messages. > > > > On Fri, 2020-03-27 at 10:50 +0100, Joerg Roedel wrote: > > > On Mon, Mar 23, 2020 at 06:49:56PM -0300, Ezequiel Garcia wrote: > > > > These user messages are not really informational, > > > > but mostly of debug nature. Lower their severity. > > > > > > Like most other messages in the kernel log, that is not a reason to > > > lower the severity. > > > > > > These messages are the first thing to look at when > > > looking into IOMMU related issues. > > > > > > > Sure, but the messages are still here, you can > > always enable them when you are looking at IOMMU issues :-) > > That still begs the question of who "you" is and how they know they're > debugging an IOMMU issue in the first place. When all the developer has > to go on is a third-hand bugzilla attachment from a distro user's vague > report of graphics corruption/poor I/O performance/boot > failure/whatever, being able to tell straight away from a standard dmesg > dump whether an IOMMU is even in the picture or not saves a lot of > protracted back-and-forth for everyone involved. > > The idea is to reduce the amount of verbosity in the kernel. > > Under what justification? Users with slow consoles or who just want a > quiet boot are already free to turn down the loglevel; a handful of > messages at boot-time and device hotplug seem hardly at risk of drowning > out all the systemd audit spam anyway. Note that the IOMMU subsystem is > by nature a little atypical as a lot of what it does is only visible as > secondary effects on other drivers and subsystems, without their > explicit involvement or knowledge. In that respect, hiding its activity > can arguably lead to more non-obvious situations than many other subsystems. > > > If all subsystems would print messages that are useful > > when looking at issues, things would be quite nasty verbose. > > From a personal standpoint, can we at least eradicate all the "Hi! I'm > a driver/subsystem you don't even have the hardware for!" messages > first, then maybe come back and reconsider the ones that convey actual > information later? > Do we really still have those??? Thanks, Ezequiel _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu