From: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
To: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, Ian Munsie <imunsie@au1.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Cc: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/2] cxl: Set VPD timeout to avoid access failures
Date: Tue, 22 Nov 2016 18:41:22 +0100 [thread overview]
Message-ID: <05398bfe-5bd4-116b-a9d7-b974d4cc032a@linux.vnet.ibm.com> (raw)
In-Reply-To: <1479762606-51632-1-git-send-email-mrochs@linux.vnet.ibm.com>
Le 21/11/2016 à 22:10, Matthew R. Ochs a écrit :
> Some IBM CXL devices can take up to ~120ms to complete a VPD access
> transaction when under heavy load. With an existing default VPD timeout
> of 50ms, reads/writes can fail despite there not being an issue with the
> underlying hardware.
>
> To avoid these false failures, increase the VPD wait timeout for certain
> CXL devices to a value that allows appropriate VPD access delay when faced
> with a worst-case scenario.
>
> Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
> ---
If the new pci API gets in, then I'm ok with the cxl change, at least
for now. For longer term, we should consider opening up the cxl kernel
API to give access to the new pci API so that it can be tuned by the AFU
driver directly, since it would know better than cxl what the proper vpd
access timeout should be.
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Fred
prev parent reply other threads:[~2016-11-22 17:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-21 21:03 [PATCH 0/2] Add device-specific VPD timeout Matthew R. Ochs
2016-11-21 21:09 ` [PATCH 1/2] PCI: Add pci_set_vpd_timeout() to set VPD access timeout Matthew R. Ochs
2016-11-21 22:05 ` Bjorn Helgaas
2016-11-22 0:15 ` Andrew Donnellan
2016-11-22 17:17 ` Stephen Hemminger
2016-11-22 0:34 ` Matthew R. Ochs
2016-11-21 21:10 ` [PATCH 2/2] cxl: Set VPD timeout to avoid access failures Matthew R. Ochs
2016-11-22 0:32 ` Andrew Donnellan
2016-11-22 0:40 ` Matthew R. Ochs
2016-11-22 17:41 ` Frederic Barrat [this message]
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