APPLIED [OEM-5.17] Re: [PATCH 0/3][SRU][Unstable/OEM-5.17] vmd: fixup bridge ASPM by driver name

[Timo Aaltonen]

You-Sheng Yang kirjoitti 11.4.2022 klo 12.24:
> From: "You-Sheng Yang (vicamo)" <vicamo.yang at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1942160
> 
> [Impact]
> 
> VMD PCI-E bridges on ADL-M/P/S use new device IDs and therefore not
> covered by previous LTR reset fix in bug 1896598.
> 
> [Fix]
> 
> Additional entires to vmd_bridge_tbl in drivers/pci/quirks.c is
> required:
> * ADL-M: [8086:464d]
> * ADL-P: [8086:51b0]
> * ADL-S: [8086:7ab4]
> 
> However, from the document there is no complete/limited set of potential
> IDs. Instead, every assigned value for VMD capable platforms can be the
> device ID for PCI bridges behind VMD controller, because these PCI
> bridges are moved from the system root bus into VMD domain.
> 
> This Ubuntu sauced patch removes matching table and check if a bridge is
> attached to a vmd module driven device.
> 
> To backport this, two additional fixes previously for bug 1889384 and
> bug 1896598 by Kai-Heng Feng are also required.
> 
> [Test Case]
> 
> $ sudo lspci -vvn | grep -E '^(1|\s+LnkCtl:)'
> ...
> 10000:e0:1d.4 0604: 8086:7ab4 (rev 10) (prog-if 00 [Normal decode])
>                  LnkCtl: ASPM L1 Enabled; RCB 64 bytes Disabled- CommClk+
> 10000:e1:00.0 0108: 8086:0975 (rev 03) (prog-if 02 [NVM Express])
>                  LnkCtl: ASPM L1 Enabled; RCB 64 bytes Disabled- CommClk+
> 
> [Where problems could occur]
> 
> This will reset zeroed PCI_LTR_MAX_SNOOP_LAT and PCI_LTR_MAX_NOSNOOP_LAT
> values to a fixed 3145728ns that is used on Windows. Devices might want
> to set itself to a smaller value, but while this is not yet correctly
> supported by VMD controller driver, so the device power consumption
> might be little worse than ideal.
> 
> [Other Info]
> 
> VMD ASPM was first supported for Tiger Lake cpus, so all kernel versions
> newer than 5.6 should have already the supporting function. This patch
> targets Alder Lake cpus that are supported since 5.13-oem and on.
> 
> Kai-Heng Feng (2):
>    UBUNTU: SAUCE: PCI/ASPM: Enable ASPM for links under VMD domain
>    UBUNTU: SAUCE: PCI/ASPM: Enable LTR for endpoints behind VMD
> 
> You-Sheng Yang (1):
>    UBUNTU: SAUCE: vmd: fixup bridge ASPM by driver name instead
> 
>   drivers/pci/pcie/aspm.c |  3 +-
>   drivers/pci/quirks.c    | 68 +++++++++++++++++++++++++++++++++++++++++
>   include/linux/pci.h     |  2 ++
>   3 files changed, 72 insertions(+), 1 deletion(-)
> 

applied to oem-5.17, thanks


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