Christoph, The first thing I see when looking at your report, is that your USB devices were plugged in via USB3 (XHCI).
Please recompile your kernel with XHCI_DEBUG, and share the debug output here (and with mpi@) when you have it, when the error happened next time. Ok? Tinker > Hello ! > > Today I experienced, that umb0 ucom0 umodem0 detached at the same > time. I can't reproduce it but saw it 1 time with snapshot #194 but > before not. [..] > xhci0 at pci0 dev 20 function 0 "Intel 8 Series xHCI" rev 0x04: msi > usb0 at xhci0: USB revision 3.0 > uhub0 at usb0 configuration 1 interface 0 "Intel xHCI root hub" rev > 3.00/1.00 addr 1 [..] > umb0 at uhub0 port 10 configuration 1 interface 0 "Sierra Wireless > Inc. Sierra Wireless EM7345 4G LTE" rev 2.00/17.29 addr 4 > umodem0 at uhub0 port 10 configuration 1 interface 2 "Sierra Wireless > ucom0 at umodem0
