On Sun, May 8, 2022 at 3:29 PM <bugzilla-daemon@kernel.org> wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=215958

            Bug ID: 215958
           Summary: thunderbolt3 egpu cannot disconnect cleanly
           Product: Drivers
           Version: 2.5
    Kernel Version: 5.17.0-1003-oem #3-Ubuntu SMP PREEMPT
          Hardware: All
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: PCI
          Assignee: drivers_pci@kernel-bugs.osdl.org
          Reporter: r087r70@yahoo.it
        Regression: No

I assume this is not a regression, right?  If it is a regression, what
previous kernel worked correctly?

I have an external egpu (Radeon 6600 RX) connected through thunderbolt3 to my
Thinkpad X1 carbon 6th Gen.. When I disconnect the thunderbolt3 cable I get the
following error in dmesg:

[21874.194994] amdgpu 0000:0c:00.0: amdgpu: SMU: response:0xFFFFFFFF for
index:18 param:0x00000005 message:TransferTableSmu2Dram?
...
...
[21879.544226] amdgpu 0000:0c:00.0: amdgpu: Failed to disable smu features.
[21879.544230] amdgpu 0000:0c:00.0: amdgpu: Fail to disable dpm features!
[21879.544238] [drm] free PSP TMR buffer

The above looks like what amdgpu would see when the GPU is no longer
accessible (writes are dropped and reads return 0xffffffff).  It's
possible amdgpu could notice this and shut down more gracefully, but I
don't think it's the main problem here and it probably wouldn't force
you to reboot.

[21880.455935] i915 0000:00:02.0: vgaarb: changed VGA decodes:
olddecodes=none,decodes=io+mem:owns=io+mem
[21880.456218] pci 0000:0c:00.0: Removing from iommu group 14
...
...
[21880.457311] pci_bus 0000:09: busn_res: [bus 09-3a] is released
[21880.457543] pci 0000:08:00.0: Removing from iommu group 14

This looks like removing 0c:00.0 (the GPU) and two switches leading to
it (probably part of the Thunderbolt topology), so to be expected.

[21880.457847] pci_bus 0000:06: Allocating resources
[21880.457888] pcieport 0000:06:02.0: bridge window [io  0x1000-0x0fff] to [bus
3b] add_size 1000
...
...
[21880.457947] pcieport 0000:06:02.0: BAR 13: failed to assign [io  size
0x1000]

I'm not sure why we're allocating resources as part of the removal.
The hierarchies under 06:02.0 (to [bus 3b]) and 06:04.0 (to [bus
3c-6f]) seem to be siblings of the hierarchy you just removed (my
guess is that was 06:01.0 to [bus 08-3a]).  But again, shouldn't
require a reboot.

upon reconnection of the cable I get:

[22192.753261] input: HDA ATI HDMI HDMI/DP,pcm=3 as
/devices/pci0000:00/0000:00:1d.0/0000:05:00.0/0000:06:01.0/0000:08:00.0/0000:09:01.0/0000:0a:00.0/0000:0b:00.0/0000:0c:00.1/sound/card1/input98
[22192.753738] input: HDA ATI HDMI HDMI/DP,pcm=7 as
/devices/pci0000:00/0000:00:1d.0/0000:05:00.0/0000:06:01.0/0000:08:00.0/0000:09:01.0/0000:0a:00.0/0000:0b:00.0/0000:0c:00.1/sound/card1/input99
[22192.753952] input: HDA ATI HDMI HDMI/DP,pcm=8 as
/devices/pci0000:00/0000:00:1d.0/0000:05:00.0/0000:06:01.0/0000:08:00.0/0000:09:01.0/0000:0a:00.0/0000:0b:00.0/0000:0c:00.1/sound/card1/input100
[22192.755234] input: HDA ATI HDMI HDMI/DP,pcm=9 as
/devices/pci0000:00/0000:00:1d.0/0000:05:00.0/0000:06:01.0/0000:08:00.0/0000:09:01.0/0000:0a:00.0/0000:0b:00.0/0000:0c:00.1/sound/card1/input101
[22192.763885] input: HDA ATI HDMI HDMI/DP,pcm=10 as
/devices/pci0000:00/0000:00:1d.0/0000:05:00.0/0000:06:01.0/0000:08:00.0/0000:09:01.0/0000:0a:00.0/0000:0b:00.0/0000:0c:00.1/sound/card1/input102
[22192.975773] thunderbolt 0-1: new device found, vendor=0x127 device=0x1
[22192.975786] thunderbolt 0-1: Razer Core X

but the egpu no longer appears in `xrandr --listproviders`. Full reboot is
needed.

Can you please build with CONFIG_DYNAMIC_DEBUG=y, boot with
'dyndbg="file pciehp* +p"', and attach the complete dmesg log to the
bugzilla?  Also please attach the complete "sudo lspci -vv" output
(before the unplug and after the replug)?