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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Sinan Kaya <okaya@codeaurora.org>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, sulrich@codeaurora.org,
timur@codeaurora.org, linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Mike Marciniszyn <mike.marciniszyn@intel.com>,
Dennis Dalessandro <dennis.dalessandro@intel.com>,
Doug Ledford <dledford@redhat.com>,
"open list:HFI1 DRIVER" <linux-rdma@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Alex Deucher <alexander.deucher@amd.com>
Subject: Re: [PATCH 1/2] IB/hfi1: Try slot reset before secondary bus reset
Date: Fri, 20 Apr 2018 08:54:00 -0600 [thread overview]
Message-ID: <20180420145400.GA30433@ziepe.ca> (raw)
In-Reply-To: <20180419214722.GO28657@bhelgaas-glaptop.roam.corp.google.com>
On Thu, Apr 19, 2018 at 04:47:23PM -0500, Bjorn Helgaas wrote:
> I *thought* the hardware was supposed to automatically negotiate to
> the highest rate supported by both sides without any help at all from
> software. But since several drivers have code to do it themselves, I
> wonder if I'm missing something, or maybe there's something the PCI
> core should be doing that it isn't, and the driver code is basically
> working around that PCI core deficiency.
The HW is supposed to do that, but Gen3 is electrically *hard*.
I'm not surprised that some HW has run into trouble where the driver
might have to be involved to tweak the SERDES.. eg there is now often
on-device software involved here and updating the SERDES 'firmware'
may be needed.
Jason
next prev parent reply other threads:[~2018-04-20 14:54 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-19 19:56 Sinan Kaya
2018-04-19 19:56 ` [PATCH 2/2] PCI/AER: " Sinan Kaya
2018-04-27 18:51 ` Sinan Kaya
2018-04-19 20:26 ` [PATCH 1/2] IB/hfi1: " Jason Gunthorpe
2018-04-19 20:35 ` Sinan Kaya
2018-04-19 21:47 ` Bjorn Helgaas
2018-04-19 22:11 ` Deucher, Alexander
2018-04-20 14:12 ` Dennis Dalessandro
2018-04-20 14:55 ` Jason Gunthorpe
2018-04-19 22:19 ` Sinan Kaya
2018-04-20 14:00 ` Bjorn Helgaas
2018-04-20 14:23 ` Sinan Kaya
2018-04-20 15:04 ` Alex Williamson
2018-04-23 17:28 ` Sinan Kaya
2018-04-23 19:10 ` Alex Williamson
2018-04-23 20:17 ` Sinan Kaya
2018-04-23 20:23 ` Bjorn Helgaas
2018-04-23 20:41 ` Alex Williamson
2018-04-25 14:13 ` Sinan Kaya
2018-04-20 14:54 ` Jason Gunthorpe [this message]
2018-06-19 21:43 ` Bjorn Helgaas
2018-06-19 22:21 ` Sinan Kaya
2018-06-22 14:01 ` Bjorn Helgaas
2018-06-22 16:04 ` Sinan Kaya
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