XHC WHB04B development?

Used the mpg today, sadly it crashed again. Loops = 10.

I actually opened an issue on github now over two years ago github.com/LinuxCNC/linuxcnc/issues/2237
No resolution. I never made a serious attempt to understand the code structure of the component.
Just looked at what was going on around the triggered assert() and made some more or less random changes.

Where is the blocking call? I'll see if I can do some ... tests.

Yeah, at least for me the loops = 10 was not the solution to everything, so not surprised the situation is the same for you. As far as I have seen, this loops = 10 would only help during a LinuxCNC mode change (auto/manual/mdi/teleop/joint).

I was not aware of that issue, so that you for bringing that up. I will write a comment there (if I can), because I think what we have discussed here is a partial solution.

I would be interesting in knowing the error message (if any) when it fails, i.e. console ouput. This I can also "generate" myself, but right now I'm not using the machine.

I think the github issue is dead so better discuss here.

It's always the same error: github.com/LinuxCNC/linuxcnc/blob/ffc393...whb04b-6/usb.cc#L465
Don't have an actual log available, pretty sure it's that line

Okay, thank you. I'm fairly certain that the reason for that message is that the pendant (dongle) has reset itself. But I don't think we know why it did so in this case. It could be something that the xhc-whb04b-6 component is doing wrong (different from the mode change delay). But it could also be that the dongle firmware is just that unstable.

I don't have any real good way to troubleshoot this. For the mode change timeout, I could capture the USB signals with a logic analyzer. But that is not feasible with my equipment if I need to wait for maybe one hour for the issue to occur. Wireshark is a possibility, but it does not show the low level packets...

I wonder what "r" is - it doesn't say.
I'll some printouts.
One can possibly dig deeper into the layers and see exactly where it fails.
One level down:
github.com/libusb/libusb/blob/dcd30cec9a...ff/libusb/io.c#L1486

The crashing doesn't respond well to provocations. I can generally get it to crash when switching modes,
but it doesn't crash when I want it to crash.

I'm pretty sure it's easiest to just add a printf("%d\n", r); between the libusb_transfer_call and the assert statement. And I'm also fairly sure I did that at one point.

And then you can just match the terminal ouput against the libusb_error enum:
github.com/libusb/libusb/blob/master/libusb/libusb.h#L1282

The docs for libusb_submit_transfer also has a section about the errors it can return and a little bit about what they mean:
libusb.sourceforge.io/api-1.0/group__lib...7dad2fee4b27962848ce