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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 6FE00C6778C for ; Tue, 3 Jul 2018 08:34:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FA1023C71 for ; Tue, 3 Jul 2018 08:34:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1FA1023C71 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933741AbeGCIew (ORCPT ); Tue, 3 Jul 2018 04:34:52 -0400 Received: from bmailout3.hostsharing.net ([176.9.242.62]:53473 "EHLO bmailout3.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932471AbeGCIeu (ORCPT ); Tue, 3 Jul 2018 04:34:50 -0400 Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (not verified)) by bmailout3.hostsharing.net (Postfix) with ESMTPS id 36391100FBEED; Tue, 3 Jul 2018 10:34:48 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id CE00C1BE91; Tue, 3 Jul 2018 10:34:47 +0200 (CEST) Date: Tue, 3 Jul 2018 10:34:47 +0200 From: Lukas Wunner To: Sinan Kaya Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Bjorn Helgaas , Oza Pawandeep , Keith Busch , open list Subject: Re: [PATCH V5 3/3] PCI: Mask and unmask hotplug interrupts during reset Message-ID: <20180703083447.GA2689@wunner.de> References: <1530571967-19099-1-git-send-email-okaya@codeaurora.org> <1530571967-19099-4-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1530571967-19099-4-git-send-email-okaya@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 02, 2018 at 06:52:47PM -0400, Sinan Kaya wrote: > If a bridge supports hotplug and observes a PCIe fatal error, the following > events happen: > > 1. AER driver removes the devices from PCI tree on fatal error > 2. AER driver brings down the link by issuing a secondary bus reset waits > for the link to come up. > 3. Hotplug driver observes a link down interrupt > 4. Hotplug driver tries to remove the devices waiting for the rescan lock > but devices are already removed by the AER driver and AER driver is waiting > for the link to come back up. > 5. AER driver tries to re-enumerate devices after polling for the link > state to go up. > 6. Hotplug driver obtains the lock and tries to remove the devices again. > > If a bridge is a hotplug capable bridge, mask hotplug interrupts before the > reset and unmask afterwards. Would it work for you if you just amended the AER driver to skip removal and re-enumeration of devices if the port is a hotplug bridge? Just check for is_hotplug_bridge in struct pci_dev. That would seem like a much simpler solution, given that it is known that the link will flap on reset, causing the hotplug driver to remove and re-enumerate devices. That would also cover cases where hotplug is handled by a different driver than pciehp, or by the platform firmware. Thanks, Lukas