XHC-WH04b USB not detected in front port

Hi Guys

I am starting to get into a swap from an older WB04 Pendant to a newer WB04B-4.

I tried the command line testing last night and noticed something really odd. The usb adaptor only apears in lsusb if connected to  rear port on the PC. If plugged into the front port it is not detected  / listed

I then plugged in the old USD adaptor for the WB04 and its apears regardless of which port I was using. 

I did some searching but didnt find anything to help, maybe you guys have a quick tip? I dont want to just blow straight past this and find it was important to my progress later on. 

Thanks Andy

Have a similar issue with a XHC-WH04b-6 on 3 industrial mini PCs I got to run my machines. On my case it does not appear in any of the ports with the lsusb command (probably haven't tested all to be fair). Tried a couple of different "rules" file I saw, plus 2 locations (one where the documentations says and other on where the 2.8 install place it).

My guess is that the internal USB hub of the computer is messing with the detection, but I have no idea on how to solve it. Tried the MPG on another old computer that a mate have with a router and it worked fine.

What I have not tried yet is to install the libprotobuf-dev and protobuf-compiler that I saw recently on the source:

github.com/LinuxCNC/linuxcnc/tree/master...r_comps/xhc-whb04b-6

Now that 2.9.1 is released I will do a fresh install and give a new try.

I booted another machine on 2.9 and found both front and 2 of 4 rear ports work ok.

Not sure it helps much but at least we know 2.9 shows same behaviour.

Ok new test: so I did a fresh install of 2.9.1 on Debian 12 Bookworm (previously tested on Buster with 2.8.4) but as I understand the problem is hardware related. Installed the libprotobuf-dev and protobuf-compiler plus created the rules file, but after testing lsusb in all ports, the MPG is not shown.

I have the same problem here with the WH04B-6. Cant see the device on any ports. I checked my bios and the legacy usb is already enabled. i enabled some other usb stuff with no results. Any luck fixing this?

FOUND IT!

After 3 years since I bought the MPG, finally found the cause and solution of the issue of not being recognized on some (or all in my case) USB ports. It probably also solve if somebody got connection problems.

The main issue is that the XHC WHB04b receptor needs quite a lot of power (comparing to other USBs) to maintain a stable connection, and not all USB ports does provide such high current. So if the connection is not stable because the power issure, the kernel does not detect it. This can also happen on windows, but the windows specific drivers solve it on some cases. My computer is an industrial mini PC with external 12V PSU, so all USBs get their 5V from the main board. On desktop computers, front forts have usually lower power than rear ones, causing the issue.

There are a couple of really easy and cheap solutions:
-Use an USB HUB with external 5V power supply
-Use a Y cable (2 male, 1 female USB) either with both male USB connectors to the computer or the power only connector to a 5V PSU.