From: Jason Gunthorpe <jgg@nvidia.com>
To: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Nicolin Chen <nicolinc@nvidia.com>,
will@kernel.org, robin.murphy@arm.com, bhelgaas@google.com,
joro@8bytes.org, praan@google.com, baolu.lu@linux.intel.com,
kevin.tian@intel.com, miko.lenczewski@arm.com,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
dan.j.williams@intel.com
Subject: Re: [PATCH v2 3/3] iommu/arm-smmu-v3: Allow ATS to be always on
Date: Tue, 24 Feb 2026 10:51:02 -0400 [thread overview]
Message-ID: <aZ261odHq5gwQYXg@nvidia.com> (raw)
In-Reply-To: <20260224120615.00003ad9@huawei.com>
On Tue, Feb 24, 2026 at 12:06:15PM +0000, Jonathan Cameron wrote:
> In my head at least, it would be nice if a driver had to explicitly opt in
> to this behavior. The presence of CXL.cache support for instance doesn't
> actually mean the driver is going to enable it. However it is probably
> harmless so lets go with this as path of least resistance.
That same remark applies to ATS in general, we have no idea if the
device is going to use it when turned on or not..
Generally Linux has taken the approach of almost always enabling ATS
if the device offers the PCIe capability.
The purpose of this series is to close of the few "almost" cases so it
is always on.
Jason
next prev parent reply other threads:[~2026-02-24 14:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-23 22:52 [PATCH v2 0/3] Allow ATS to be always on for certain ATS-capable devices Nicolin Chen
2026-02-23 22:52 ` [PATCH v2 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices Nicolin Chen
2026-02-24 11:55 ` Jonathan Cameron
2026-02-24 18:43 ` Nicolin Chen
2026-03-03 3:18 ` Baolu Lu
2026-03-03 20:15 ` Nicolin Chen
2026-02-23 22:52 ` [PATCH v2 2/3] PCI: Allow ATS to be always on for pre-CXL devices Nicolin Chen
2026-02-23 22:52 ` [PATCH v2 3/3] iommu/arm-smmu-v3: Allow ATS to be always on Nicolin Chen
2026-02-24 12:06 ` Jonathan Cameron
2026-02-24 14:51 ` Jason Gunthorpe [this message]
2026-02-24 15:57 ` Jonathan Cameron
2026-02-24 16:09 ` Jason Gunthorpe
2026-03-02 14:54 ` Jonathan Cameron
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=aZ261odHq5gwQYXg@nvidia.com \
--to=jgg@nvidia.com \
--cc=baolu.lu@linux.intel.com \
--cc=bhelgaas@google.com \
--cc=dan.j.williams@intel.com \
--cc=iommu@lists.linux.dev \
--cc=jonathan.cameron@huawei.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=miko.lenczewski@arm.com \
--cc=nicolinc@nvidia.com \
--cc=praan@google.com \
--cc=robin.murphy@arm.com \
--cc=will@kernel.org \
/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