Re: USB issue on a TB4 controller?

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 26.5.2023 15.36, Mika Westerberg wrote:
> 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.

Also worth testing if rebinding/resetting the 4 port USB 3.1 hub built into the dock with
the NIC connected to it helps.

# echo "4-2:1.0" > /sys/bus/usb/drivers/hub/unbind
# echo "4-2:1.0" > /sys/bus/usb/drivers/hub/bind

Thanks
-Mathias