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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA8E5C07545 for ; Tue, 24 Oct 2023 09:33:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234297AbjJXJdu (ORCPT ); Tue, 24 Oct 2023 05:33:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234061AbjJXJdg (ORCPT ); Tue, 24 Oct 2023 05:33:36 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F7C03259; Tue, 24 Oct 2023 02:32:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B569C433C7; Tue, 24 Oct 2023 09:32:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698139964; bh=UPQBF1hjWZNZJzepFfkVdTlAkejOqi2qCPHFJIJlpoo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=1yRUBc8YUTQyJ3mKxupBcm8GBt5PJZ82/ESPqSF3ssB3JJfGEg1YaqKI/fYTogBPM WVxqdjED8e1T7WhoxBzzvaZzA7qVJ7CO7CRW9AoAnOM85CmkLqckbMumWTm0jjs/BZ SA8McnxFrETIDIRO1STRzZm/qBwhUsU7ueYbeC4k= Date: Tue, 24 Oct 2023 11:32:41 +0200 From: Greg KH To: Dan Raymond Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-serial , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, andriy.shevchenko@linux.intel.com, quic_saipraka@quicinc.com, Steven Rostedt Subject: Re: [PATCH v5] arch/x86: port I/O tracing on x86 Message-ID: <2023102406-prodigal-evidence-471d@gregkh> References: <2023100344-dart-jailbreak-c371@gregkh> <94e2b77c-9cc4-534f-e650-06d7e0697f9f@gmail.com> <20231004195001.76a57417@gandalf.local.home> <80b84be0-a0ad-d1a9-607a-a87c6cf509e0@gmail.com> <2023102122-diabetes-trend-57d0@gregkh> <62349c78-14b8-4d5c-87ea-00dbd662fe26@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <62349c78-14b8-4d5c-87ea-00dbd662fe26@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Mon, Oct 23, 2023 at 02:28:04PM -0600, Dan Raymond wrote: > > Anyway, it's up to the x86 maintainers now, good luck! > > > > But personally, I don't see the real need for this at all. It's a > > debugging thing for what exactly? Who needs this? Who will use it? > > When will they use it? And why? > > This comment confuses me. As you know I originally submitted a patch > that added I/O tracing just to the 8250 serial driver. The patch was > titled "create debugfs interface for UART register tracing". You said > this at the time: > > "Anyway, again, cool feature, I like it, but if you can tie it into > the existing trace framework better (either by using that entirely > which might be best), or at the least, putting your hook into the > data path with it, that would be best." Remember some of us, like myself, get on average 1000+ emails a day that they need to file/delete/review, so what I wrote yesterday I usually can't remember, let alone weeks ago :) > My original patch went through a few revisions before Andy Shevchenko > suggested I should add portio tracing instead in a manner similar to > how CONFIG_TRACE_MMIO_ACCESS works. You agreed. Hence I created this > patch. That's great, but it turns out that the x86 maintainers don't like this, so perhaps that's not going to work out well. I still think the original idea of using tracepoints for serial data would be best, but hey, I don't need this feature :) thanks, greg k-h