uchcom USB-serial

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

I purchased a couple of USB-serial adapters. Unfortunately, given the lack
of detail in the descriptions, they turned out to be

  uchcom0: QinHeng Electronics (0x1a86) USB2.0-Ser! (0x7523), rev 1.10/2.54

According to

  https://nxr.netbsd.org/xref/src/sys/dev/usb/uchcom.c#40

this is "the worst USB-serial chip in the world."

Do these work at all? (Get "tip: link down", then change to a 
uplcom0: Prolific Technology Inc. and all is well.)


Cheers,

Patrick