From: Bjorn Helgaas <helgaas@kernel.org>
To: Wu Zongyong <wuzongyong@linux.alibaba.com>
Cc: sdonthineni@nvidia.com, bhelgaas@google.com,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
wllenyj@linux.alibaba.com, wutu.xq2@linux.alibaba.com,
gerry@linux.alibaba.com
Subject: Re: [RFC PATCH] PCI: avoid SBR for NVIDIA T4
Date: Thu, 30 Mar 2023 10:49:26 -0500 [thread overview]
Message-ID: <20230330154926.GA3150990@bhelgaas> (raw)
In-Reply-To: <20230330021016.GA30164@L-PF27918B-1352.localdomain>
On Thu, Mar 30, 2023 at 10:10:16AM +0800, Wu Zongyong wrote:
> On Wed, Mar 29, 2023 at 12:05:15PM -0500, Bjorn Helgaas wrote:
> > On Wed, Mar 29, 2023 at 07:58:45PM +0800, Wu Zongyong wrote:
> > > Secondary bus reset will fail if NVIDIA T4 card is direct attached to a
> > > root port.
> >
> > Is this only a problem when direct attached to a Root Port? Why would
> > that be? If it's *not* related to being directly under a Root Port,
> > don't mention that at all.
>
> Yes, this problem occurs only when the T4 card is direct attached to a
> Root Port.
> I have test it with a T4 card attached to a PCIe Switch or a PCI Bridge,
> and it works well.
From an electrical and protocol point of view, the device should not
be able to tell the difference, so Lukas' suggestion that it may be
related to reset delays seems very pertinent.
Bjorn
next prev parent reply other threads:[~2023-03-30 15:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-29 11:58 [RFC PATCH] PCI: avoid SBR for NVIDIA T4 Wu Zongyong
2023-03-29 17:05 ` Bjorn Helgaas
2023-03-30 2:10 ` Wu Zongyong
2023-03-30 15:49 ` Bjorn Helgaas [this message]
2023-03-31 2:11 ` Wu Zongyong
2023-04-03 4:02 ` Wu Zongyong
2023-03-30 2:41 ` Lukas Wunner
2023-04-10 12:34 ` [PATCH] PCI: Mark NVIDIA T4 GPUs to avoid bus reset Wu Zongyong
2023-04-26 8:13 ` Wu Zongyong
2023-08-09 23:05 ` Bjorn Helgaas
2023-09-08 2:50 ` Wu Zongyong
2023-09-08 3:40 ` Alex Williamson
2023-09-08 20:11 ` Bjorn Helgaas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230330154926.GA3150990@bhelgaas \
--to=helgaas@kernel.org \
--cc=bhelgaas@google.com \
--cc=gerry@linux.alibaba.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=sdonthineni@nvidia.com \
--cc=wllenyj@linux.alibaba.com \
--cc=wutu.xq2@linux.alibaba.com \
--cc=wuzongyong@linux.alibaba.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox