[SRU] [D/E/Unstable/OEM-B] [PATCH 0/7] Make hotplugging docking station to Thunderbolt port more reliable

[Thadeu Lima de Souza Cascardo]

On Tue, Nov 26, 2019 at 04:51:42PM +0800, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/1853991
> 
> [Impact]
> Sometimes USB ports and USB ethernet on Thunderbolt Docking don't work
> after hotplugging.
> 
> [Fix]
> Add proper link delay when PCIe devices transit out from D3cold.
> 
> [Test]
> Tested with Dell WD19DC docking station on Dell XPS 9380. After applying
> the fix, the USB ports on docking always work after hotplugging.
> 
> [Regression Potential]
> Low. This patch series adds proper delay required by PCIe spec, and only
> affects hotplug ports, i.e. Thunderbolt.

That doesn't seem like a correct statement. The last commit mentions a previous
attempt was reverted because of regressions. And it's backported from
linux-next.

By reading the code, it seems it could at least cause some delays during
resume, but I would like to see this better tested to show that's likely the
most that could happen.

Could you test other systems and look for problems during suspend-resume tests?

Thanks.
Cascardo.

> 
> Felipe Balbi (1):
>   PCI: Add support for Immediate Readiness
> 
> Keith Busch (1):
>   PCI: Make link active reporting detection generic
> 
> Mika Westerberg (3):
>   PCI: Make pcie_downstream_port() available outside of access.c
>   PCI/PM: Add pcie_wait_for_link_delay()
>   PCI/PM: Add missing link delays required by the PCIe spec
> 
> Oza Pawandeep (1):
>   PCI/DPC: Clear interrupt status in interrupt handler top half
> 
> Rafael J. Wysocki (1):
>   PCI: PM: Avoid skipping bus-level PM on platforms without ACPI
> 
>  drivers/pci/access.c             |   9 --
>  drivers/pci/hotplug/pciehp_hpc.c |  22 +---
>  drivers/pci/pci-driver.c         |  17 ++-
>  drivers/pci/pci.c                | 180 +++++++++++++++++++++++++++++--
>  drivers/pci/pci.h                |  10 ++
>  drivers/pci/pcie/dpc.c           |   7 +-
>  drivers/pci/probe.c              |   1 +
>  include/linux/pci.h              |   2 +
>  include/linux/suspend.h          |  26 ++++-
>  include/uapi/linux/pci_regs.h    |   1 +
>  kernel/power/suspend.c           |   3 +
>  11 files changed, 233 insertions(+), 45 deletions(-)
> 
> -- 
> 2.17.1
> 
> 
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