Fwd: [Bug 216000] New: TBT storage hotplug fail when connect via thunderbolt dock

Fwd: [Bug 216000] New: TBT storage hotplug fail when connect via thunderbolt dock

[Bjorn Helgaas]

Thanks for the report, Chris!  Forwarding to linux-pci and Lukas for visibility.

---------- Forwarded message ---------
From: <bugzilla-daemon@kernel.org>
Date: Thu, May 19, 2022 at 9:24 AM
Subject: [Bug 216000] New: TBT storage hotplug fail when connect via
thunderbolt dock
To: <bjorn@helgaas.com>

https://bugzilla.kernel.org/show_bug.cgi?id=216000

            Bug ID: 216000
           Summary: TBT storage hotplug fail when connect via thunderbolt
                    dock
           Product: Drivers
           Version: 2.5
    Kernel Version: 5.17 and later
          Hardware: Intel
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: PCI
          Assignee: drivers_pci@kernel-bugs.osdl.org
          Reporter: chris.chiu@canonical.com
        Regression: No

Created attachment 300996
  --> https://bugzilla.kernel.org/attachment.cgi?id=300996&action=edit
output of lspci -vvv

When I power on the adl-hx laptop with the thuderbolt dock(Dell WD22TB4)
connected, the TBT storage can never be detected if I connect it via the dock.
The kernel message shows "No bus number available for hot-added bridge" as
follows.

[  102.073815] pcieport 0000:3a:01.0: pciehp: Slot(1-1): Card present
[  102.073825] pcieport 0000:3a:01.0: pciehp: Slot(1-1): Link Up
[  102.210491] pci 0000:3c:00.0: [8086:15da] type 01 class 0x060400
[  102.210702] pci 0000:3c:00.0: enabling Extended Tags
[  102.211176] pci 0000:3c:00.0: supports D1 D2
[  102.211179] pci 0000:3c:00.0: PME# supported from D0 D1 D2 D3hot D3cold
[  102.211510] pci 0000:3c:00.0: 8.000 Gb/s available PCIe bandwidth, limited
by 2.5 GT/s PCIe x4 link at 0000:03:03.0 (capable of 31.504 Gb/s with 8.0 GT/s
PCIe x4 link)
[  102.211732] pci 0000:3c:00.0: Adding to iommu group 30
[  102.212093] pcieport 0000:3a:01.0: ASPM: current common clock configuration
is inconsistent, reconfiguring
[  102.212172] pci 0000:3c:00.0: No bus number available for hot-added bridge

The problem will be gone if I boot with the kernel parameter
"pci=realloc,assign-busses,hpbussize=0x33" but we expect the `pciehp` should
handle it w/o problem. Which part of system should reserve the PCIe bus number
the hotplug device?

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