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, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 24578C433DB for ; Fri, 22 Jan 2021 08:55:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDFFD236F9 for ; Fri, 22 Jan 2021 08:55:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727261AbhAVIzG (ORCPT ); Fri, 22 Jan 2021 03:55:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727257AbhAVIy7 (ORCPT ); Fri, 22 Jan 2021 03:54:59 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2A56C0613D6 for ; Fri, 22 Jan 2021 00:54:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Mime-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xcWJRkL/6Aj2T3db6h/zTR5N13JB7aT6FcITKLkzYEw=; b=A8oyfGNGkwy4g0xitVz5XaWDJO hLrlpKkV5nknecDku7dZDAJbBC3EYA02Aq1deo591BZXH6A1ztcJ2Fn/Sqzb9EXZItIuMUnzEDhV8 TmIzxVmfjpZJs/GzgTZX2CIqZrMw8BNnaNBEBWEKQ1FNeS5zonH4ruaTaDeCATWu10wCuQ12+CEmF neZoJV9mKy1X102n03/dD9qJ7LKwEmfuJksjip1NV77D/8fa2a+RZRKKKS2GTkGSLbB7sg4UAbFJc NtjfcLyBYz+V2KvxyyM4WoMuSvudILo6kdfZC5M1gayzyOdiEAbq6lTYEhtb4GVijzy+E4LejQkgm ISlRRbrw==; Received: from [54.239.6.187] (helo=freeip.amazon.com) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2sCs-0001LC-TK; Fri, 22 Jan 2021 08:54:15 +0000 Message-ID: <8c9c45025b6130719d23c2fe151e2b6d3eef3baf.camel@infradead.org> Subject: Re: [PATCH v4 0/3] Improve PCI device post-reset readiness polling From: David Woodhouse To: Stanislav Spassov , linux-pci@vger.kernel.org Cc: Stanislav Spassov , Bjorn Helgaas , Thomas Gleixner , Andrew Morton , "Jan H ." =?ISO-8859-1?Q?Sch=F6nherr?= , Jonathan Corbet , Ashok Raj , Alex Williamson , Sinan Kaya , Rajat Jain Date: Fri, 22 Jan 2021 08:54:12 +0000 In-Reply-To: <20200307172044.29645-1-stanspas@amazon.com> References: <20200307172044.29645-1-stanspas@amazon.com> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-I+Kyh1bR+2vwj+lFfsLA" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org --=-I+Kyh1bR+2vwj+lFfsLA Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, 2020-03-07 at 18:20 +0100, Stanislav Spassov wrote: > From: Stanislav Spassov >=20 > The first version of this patch series can be found here: > https://lore.kernel.org/linux-pci/20200223122057.6504-1-stanspas@amazon.c= om >=20 > The goal of this patch series is to solve an issue where pci_dev_wait > can cause system crashes. After a reset, a hung device may keep > responding with CRS completions indefinitely. If CRS Software Visibility > is enabled on the Root Port, attempting to read any register other than > PCI_VENDOR_ID will cause the Root Port to autonomously retry the request > without reporting back to the CPU core. Unless the number of retries or > the amount of time spent retrying is limited by platform-specific means, > this scenario leads to low-level platform timeouts (such as a TOR > Timeout), which can easily escalate to a crash. >=20 > Feedback on the v1 inspired a lot of additional improvements all around t= he > device reset codepaths and reducing post-reset delays. These improvements > were published as part of v2 (v3 is just small build fixes). >=20 > It looks like there is immediate demand specifically for the CRS work, > so I am once again reducing the series to just that. The reset will be > posted as a separate patch series that will likely require more time and > iterations to stabilize. Hm, what happened to this? 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