From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Subject: Re: [PATCH 2/2] pci: Don't set RCB bit in LNKCTL if the upstream bridge hasn't To: Johannes Thumshirn , Bjorn Helgaas References: <20161102223552.14776-1-jthumshirn@suse.de> <20161102223552.14776-2-jthumshirn@suse.de> <20161109171140.GK14322@bhelgaas-glaptop.roam.corp.google.com> <20161114115604.gzxjstjj7vb4ytno@linux-x5ow.site> Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Graf , Hannes Reinecke From: Don Dutile Message-ID: <5829E373.1070901@redhat.com> Date: Mon, 14 Nov 2016 11:16:51 -0500 MIME-Version: 1.0 In-Reply-To: <20161114115604.gzxjstjj7vb4ytno@linux-x5ow.site> Content-Type: text/plain; charset=utf-8; format=flowed List-ID: On 11/14/2016 06:56 AM, Johannes Thumshirn wrote: > On Wed, Nov 09, 2016 at 11:11:40AM -0600, Bjorn Helgaas wrote: >> Hi Johannes, >> >> On Wed, Nov 02, 2016 at 04:35:52PM -0600, Johannes Thumshirn wrote: >>> The Read Completion Boundary (RCB) bit must only be set on a device or >>> endpoint if it is set on the root complex. >>> >>> Certain BIOSes erroneously set the RCB Bit in their ACPI _HPX Tables >>> even if it is not set on the root port. This is a violation to the PCIe >>> Specification and is known to bring some Mellanox Connect-X 3 HCAs into >>> a state where they can't map their firmware and go into error recovery. >>> >>> BIOS Information >>> Vendor: IBM >>> Version: -[A8E120CUS-1.30]- >>> Release Date: 08/22/2016 >> >> This seems like a pretty serious problem (sounds like maybe the HCA is >> completely useless?) > > Correct. > >> >> Can you point us at a bugzilla or other problem report? It's nice to >> have details of what this looks like to a user, so people who trip >> over this problem have a little more chance of finding the solution. > > As we already said, our bugzilla entry for this is not accessible from the > outside, but I know Red Hat does have a bugzilla entry for the same issue as > well. Maybe this is reachable from the outside (adding Don for this, as I know > he has worked on this problem as well). > RHEL bz's are not accessible from the outside. I suggest capturing the content of the RH bz issue and creating a k.o. bz with the information. >> >> 7a1562d4f2d0 ("PCI: Apply _HPX Link Control settings to all devices >> with a link") appeared in v3.18, so it's probably not a *new* problem, >> so my guess is that this is v4.10 material. > > Yes 4.10 sounds good to me. I personally think, this problem hasn't > materialized yet, as this is the kind of hardware you run on a rather /stable/ > kernel either you built on your own or get from an enterprise distribution and > until recently these kernels haven't been updated to something newer than > 3.18. > > Thanks, > Johannes >