From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: To: Bjorn Helgaas , Stephen Bates Cc: "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "linux-rdma@vger.kernel.org" , "linux-nvdimm@lists.01.org" , "linux-block@vger.kernel.org" , Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson References: <20180228234006.21093-1-logang@deltatee.com> <20180228234006.21093-5-logang@deltatee.com> <20180301180257.GH13722@bhelgaas-glaptop.roam.corp.google.com> <0D05579B-789C-4A19-B3A2-C1A630BE31C0@raithlin.com> <20180301231536.GB74737@bhelgaas-glaptop.roam.corp.google.com> From: Logan Gunthorpe Message-ID: Date: Thu, 1 Mar 2018 16:59:27 -0700 MIME-Version: 1.0 In-Reply-To: <20180301231536.GB74737@bhelgaas-glaptop.roam.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Subject: Re: [PATCH v2 04/10] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches List-ID: On 01/03/18 04:15 PM, Bjorn Helgaas wrote: > The question is what the relevant switch is. We call pci_enable_acs() > on every PCI device, including Root Ports. It looks like this relies > on get_upstream_bridge_port() to filter out some things. I don't > think get_upstream_bridge_port() is doing the right thing, so we need > to sort that out first, I guess. Yes, well if a port has an upstream bridge port and that port has an upstream bridge port we are almost certainly looking at a port in a switch. If you have a better suggestion to only disable ACS bits on downstream switch ports I'd be happy to consider it. > This might be a good start, but whatever the implications are, they > need to be distilled and made clear directly in the changelog and the > Kconfig help text. Well, I tried. I'll expand on it for v3. Logan