From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:44126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933423AbcKNVDW (ORCPT ); Mon, 14 Nov 2016 16:03:22 -0500 Date: Mon, 14 Nov 2016 15:03:19 -0600 From: Bjorn Helgaas To: Alex Williamson Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/5] PCI: Balance ports to avoid ACS errata on Pericom switches Message-ID: <20161114210319.GC9868@bhelgaas-glaptop.roam.corp.google.com> References: <20161026175156.23495.12980.stgit@gimli.home> <20161026180140.23495.27388.stgit@gimli.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20161026180140.23495.27388.stgit@gimli.home> Sender: linux-pci-owner@vger.kernel.org List-ID: On Wed, Oct 26, 2016 at 12:01:40PM -0600, Alex Williamson wrote: > As described in the included code comment, this quirk is intended to > work around an errata in a variety of Pericom 4-lane, 3 and 4 port > PCIe 2.0 switches. The switches advertise ACS capabilities, but the > P2P Request Redirection support includes an errata that PCI_ACS_RR > effectively doesn't work and results in transactions being queued and > not delivered within the PCIe switch. The errata has no planned > hardware fix. Is there a published erratum we can reference here? It'd be really nice to have a URL.