[SRU] [L/M/Unstable] [PATCH 0/9] Enable ASPM for NVMe behind VMD

[Kai-Heng Feng]

On Wed, Sep 6, 2023 at 4:08 PM Stefan Bader <stefan.bader at canonical.com> wrote:
>
> On 06.09.23 09:54, Kai-Heng Feng wrote:
> > BugLink: https://bugs.launchpad.net/bugs/2034504
> >
> > [Impact]
> > ASPM of NVMe behind VMD is not enabled when BIOS FADT doesn't allow ASPM
> > to be modified.
> > That causes higher overall power consumption.
> >
> > [Fix]
> > Allow ASPM to be enabled.
> > While at this, remove old cruft that can interfere upstream VMD driver.
> >
> > [Test]
> > Check the value of `/sys/kernel/debug/pmc_core/slp_s0_residency_usec`.
> > Now system can reach deepest power saving state during sleep.
> >
> > [Where problems could occur]
> > Some NVMe may have I/O issue when ASPM is enabled. But for this scenario
> > the issue will also appear when VMD is disabled.
> >
> > David E. Box (3):
> >    PCI: vmd: Use PCI_VDEVICE in device list
> >    PCI: vmd: Create feature grouping for client products
> >    PCI: vmd: Add quirk to configure PCIe ASPM and LTR
> >
> > Kai-Heng Feng (5):
> >    Revert "UBUNTU: SAUCE: vmd: fixup bridge ASPM by driver name instead"
> >    Revert "UBUNTU: SAUCE: PCI/ASPM: Enable LTR for endpoints behind VMD"
> >    Revert "UBUNTU: SAUCE: PCI/ASPM: Enable ASPM for links under VMD
> >      domain"
> >    UBUNTU: SAUCE: PCI/ASPM: Allow ASPM override over FADT default
> >    UBUNTU: SAUCE: PCI: vmd: Mark ASPM override for device behind VMD
> >      bridge
> >
> > Michael Bottini (1):
> >    PCI/ASPM: Add pci_enable_link_state()
> >
> >   drivers/pci/controller/vmd.c | 100 ++++++++++++++++++++++++++---------
> >   drivers/pci/pcie/aspm.c      |  54 +++++++++++++++++++
> >   drivers/pci/quirks.c         |  68 ------------------------
> >   include/linux/pci.h          |   7 +++
> >   4 files changed, 135 insertions(+), 94 deletions(-)
> >
>
> What is the outlook/current stage of these 2 new SAUCE patches. Under
> discussion, somewhere in the upstream pipe?

I am actively working on a series to enable ASPM for both VMD and
hotplugged PCIe devices, so the final form may differ.

Kai-Heng

>
> -Stefan