From: Kai-Heng Feng <kai.heng.feng@canonical.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "Bjorn Helgaas" <bhelgaas@google.com>,
"Heiner Kallweit" <hkallweit1@gmail.com>,
"Anthony Wong" <anthony.wong@canonical.com>,
"Linux PCI" <linux-pci@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Vidya Sagar" <vidyas@nvidia.com>,
"Logan Gunthorpe" <logang@deltatee.com>
Subject: Re: [PATCH v2 3/3] PCI/ASPM: Add LTR sysfs attributes
Date: Thu, 28 Oct 2021 13:16:31 +0800 [thread overview]
Message-ID: <CAAd53p5g++fHfOi9WUVm2aHo+4C9AssFcA1dB0AMt9rBwsKTnQ@mail.gmail.com> (raw)
In-Reply-To: <20211026165348.GA146058@bhelgaas>
On Wed, Oct 27, 2021 at 12:53 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Tue, Oct 26, 2021 at 10:28:38AM +0800, Kai-Heng Feng wrote:
>
> > What if we fallback to the original approach and use the VMD driver
> > to enable ASPM and LTR values? At least I think Intel should be
> > able to provide correct values for their SoC.
>
> Can you post the patches for that? I'm not sure exactly what the
> original approach was. Are these the same as the downstream support
> you mention below?
This is the previous attempt to enable VMD ASPM:
https://lore.kernel.org/linux-pci/20200930082455.25613-1-kai.heng.feng@canonical.com/
It didn't enable LTR though.
Right now the downstream kernel use PCI quirk to enable VMD ASPM and LTR:
https://kernel.ubuntu.com/git/ubuntu/unstable.git/commit/?id=069ab00c2613d27cb7cdeb2a4c751de89dab81b4
https://kernel.ubuntu.com/git/ubuntu/unstable.git/commit/?id=1e4dec5fe846f8dd8954b173434670f8ae30b5ff
The patches don't touch VMD driver to minimize merge conflict on VMD driver.
I really hope we can put these changes to upstream VMD driver.
Kai-Heng
>
> > So what other options do we have if we want to enable VMD ASPM while
> > keeping CONFIG_PCIEASPM_DEFAULT=y? Right now we enabled the VMD
> > ASPM/LTR bits in downstream kernel, but other distro users may want
> > to have upstream support for this.
prev parent reply other threads:[~2021-10-28 5:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 3:51 [PATCH v2 0/3] Let user enable ASPM and LTR via sysfs Kai-Heng Feng
2021-10-21 3:51 ` [PATCH v2 1/3] PCI/ASPM: Store disabled ASPM states Kai-Heng Feng
2021-10-21 3:51 ` [PATCH v2 2/3] PCI/ASPM: Use capability to override ASPM via sysfs Kai-Heng Feng
2021-10-21 3:51 ` [PATCH v2 3/3] PCI/ASPM: Add LTR sysfs attributes Kai-Heng Feng
2021-10-21 15:09 ` Bjorn Helgaas
2021-10-25 10:33 ` Kai-Heng Feng
2021-10-25 17:31 ` Bjorn Helgaas
2021-10-26 2:28 ` Kai-Heng Feng
2021-10-26 16:53 ` Bjorn Helgaas
2021-10-28 5:16 ` Kai-Heng Feng [this message]
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