Re: USB issue on a TB4 controller?

[Mika Westerberg <mika.westerberg@linux.intel.com>]

Hi,

On Tue, May 23, 2023 at 01:15:30PM +0200, Christian Schaubschläger wrote:
> Hi Mika,
> 
> attached you find two dmesg logs (with tunderbolt.dyndbg=+p), one from power off state were everything is ok (dmesg_ok.txt.xz).
> The second one (dmesg_nok.txt.xz) is after a reboot when the network interface is in faulty state.
> 
> Hardware is:
> Dell Inc. Latitude 7440/0XDRJY, BIOS 1.3.1 04/25/2023
> CPU0: 13th Gen Intel(R) Core(TM) i5-1345U (family: 0x6, model: 0xba, stepping: 0x3)
> thunderbolt 0-1: Dell WD19TB Thunderbolt Dock

Sorry for the delay. I've been busy with some other issues.

I guess we are talking about this xHCI:

[   15.449690] xhci_hcd 0000:04:00.0: xHCI Host Controller
[   15.450477] xhci_hcd 0000:04:00.0: new USB bus registered, assigned bus number 3
[   15.452337] xhci_hcd 0000:04:00.0: hcc params 0x200077c1 hci version 0x110 quirks 0x00
00000200009810
[   15.453734] xhci_hcd 0000:04:00.0: xHCI Host Controller
[   15.454437] xhci_hcd 0000:04:00.0: new USB bus registered, assigned bus number 4
[   15.455092] xhci_hcd 0000:04:00.0: Host supports USB 3.1 Enhanced SuperSpeed

In both cases the the SuperSpeed HUB is found:

[    5.589178] usb 4-2.3: new SuperSpeed USB device number 3 using xhci_hcd
[    5.622113] input: HDA Intel PCH Headphone Mic as /devices/pci0000:00/0000:00:1f.3/soun
d/card0/input27
[    5.635536] hub 4-2.3:1.0: USB hub found
[    5.637176] hub 4-2.3:1.0: 4 ports detected

However, the connected NIC is only found in dmesg_ok.txt.xz:

[    5.904363] usb 4-2.4: new SuperSpeed USB device number 4 using xhci_hcd
...
[    6.192613] r8152-cfgselector 4-2.4: reset SuperSpeed USB device number 4 using xhci_hcd
[    6.217838] r8152 4-2.4:1.0 (unnamed net_device) (uninitialized): Using pass-thru MAC addr ac:91:a1:95:63:bf
[    6.258478] r8152 4-2.4:1.0: load rtl8153b-2 v1 10/23/19 successfully
[    6.318568] r8152 4-2.4:1.0 eth0: v1.12.13

To me it looks like the PCIe tunnel to the xHCI (0000:04:00.0) on the
dock works fine, otherwise it would not show up at all. I'm not an xHCI
expert so adding Mathias in case he has ideas how to debug this further.

I think it makes sense to enable xHCI debugging and traces and provide
them to Mathias. The following commands should do so:

 # echo 'module xhci_hcd =p' >/sys/kernel/debug/dynamic_debug/control
 # echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control
 # echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb
 # echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable

Trace buffer is /sys/kernel/debug/tracing/trace.