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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 24017C07E9C for ; Wed, 14 Jul 2021 16:49:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A89E61279 for ; Wed, 14 Jul 2021 16:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236955AbhGNQwn (ORCPT ); Wed, 14 Jul 2021 12:52:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229597AbhGNQwm (ORCPT ); Wed, 14 Jul 2021 12:52:42 -0400 X-Greylist: delayed 14394 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 14 Jul 2021 09:49:50 PDT Received: from mta02.hs-regensburg.de (mta02.hs-regensburg.de [IPv6:2001:638:a01:1096::12]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F858C06175F; Wed, 14 Jul 2021 09:49:50 -0700 (PDT) Received: from E16S03.hs-regensburg.de (e16s03.hs-regensburg.de [IPv6:2001:638:a01:8013::93]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "E16S03", Issuer "E16S03" (not verified)) by mta02.hs-regensburg.de (Postfix) with ESMTPS id 4GQ3Q20s3WzyKH; Wed, 14 Jul 2021 18:49:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oth-regensburg.de; s=mta01-20160622; t=1626281386; bh=HdkPsmS3CzfxqWjY4kwQysyY+bLPHmZ79xZMXkjw4fU=; h=Subject:To:CC:References:From:Date:In-Reply-To:From; b=tgealBdl26o+0+dexJXGzOHmoaXVW3u2KOc3u2Mg8tGYx8/AbuYRC2rvFRCmE1Qui qOLHZpD4caKTbCL8GOLGNOS5XEZxhUJQ9DmRIjhrsla7ROUMjFUWXI5xWX4jok4At2 MoG6bp6kDsV25rbWHuHHuRJ/U6F9Q8Et8HB+wwMldDUSKkpsQ7nOMzqZ5DPhfz6Ypd VMQDLqu9vbyMTuIsyEj8H7pF9UMrR+76dUEDvH0+loLuxAUjjPEoek+RJ3EYjh2DC9 cIK3HsbFBLxg8zo4/JJm+599sFAqRsFGAPdrvCbDDd8J2fak3G7OXF2M1P8/0PdWRj zhh5cH1B26p4g== Received: from [IPv6:2001:678:ddc:11:17a4:3bb5:620b:1dcb] (2001:638:a01:8013::138) by E16S03.hs-regensburg.de (2001:638:a01:8013::93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2242.10; Wed, 14 Jul 2021 18:49:45 +0200 Subject: Re: [EXT] Re: [PATCH v1 3/4] serial: 8250_pci: Always try MSI/MSI-X To: Andy Shevchenko CC: Jiri Slaby , Andy Shevchenko , , , Greg Kroah-Hartman References: <20210713104026.58560-1-andriy.shevchenko@linux.intel.com> <20210713104026.58560-3-andriy.shevchenko@linux.intel.com> <9af24b96-8119-7ccf-f0d0-d725af80aa0b@kernel.org> <784629f9-677e-ee53-aceb-89397ce0951a@oth-regensburg.de> From: Ralf Ramsauer Message-ID: <0a15be25-d4e1-f2f5-22f7-6144b7100bf1@oth-regensburg.de> Date: Wed, 14 Jul 2021 18:49:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [2001:638:a01:8013::138] X-ClientProxiedBy: E16S01.hs-regensburg.de (2001:638:a01:8013::91) To E16S03.hs-regensburg.de (2001:638:a01:8013::93) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/07/2021 15:35, Andy Shevchenko wrote: > On Wed, Jul 14, 2021 at 3:56 PM Ralf Ramsauer > wrote: >> On 14/07/2021 08:54, Jiri Slaby wrote: >>> On 13. 07. 21, 12:40, Andy Shevchenko wrote: > >>> Hmm, have you checked the commit which introduced the whitelist? >>> >>> Nevertheless, this needs to handled with care: while many 8250 devices >>> actually claim to support MSI(-X) interrupts it should not be >>> enabled be >>> default. I had at least one device in my hands with broken MSI >>> implementation. >>> >>> So better introduce a whitelist with devices that are known to support >>> MSI(-X) interrupts. I tested all devices mentioned in the patch. >>> >>> >>> You should have at least CCed the author for an input. >> >> Yep, back then I was testing three different 8250 pci cards. All of them >> claimed to support MSI, while one really worked with MSI, the one that I >> whitelisted. So I thought it would be better to use legacy IRQs as long >> as no one tested a specific card to work with MSI. > > Can you shed a light eventually what those cards are? That's been a while. Let me check that if I can still find them, and I'll test them once again against MSI being enabled. But this can take some days. Ralf > >> Don't do that… And don't convert it to a blacklist. A blacklist will >> break users until they report that something doesn't work. > > White list is not okay either. MSI in general is a right thing to do. > preventing users from MSI is asking for the performance degradation > and IRQ resource conflicts (in case the IRQ line is shared). > > Besides that, shouldn't it be rather the specific field in private (to > 8250_pci) structure than constantly growing list?