On Wed, 27 May 2020 22:22:20 -0400, Peter Stuge wrote: ... > On rev03, PCs can only try to use a heuristic with the RPC protocol to > guess if the board is running/available or not. > > This proposed USB interface is self-powered, by VCCO_3V3, so when this > interface is connected to a PC the USB device comes and goes on the PC > as the 18V supply is connected and disconnected from the rev04 board. > > Is that change desirable?
The only reason I can think of why the host side might care is if the OS drivers are going to renumber the USB device every time it appears. Otherwise, I don't see why the host would expect the HSM to do anything in particular when not powered. What I would like very much, though, if it's not a lot of trouble, would be some way for the host side to identify these USB devices easily and tell them apart from each other. What we do right now is seriously disgusting: we look for USB devices matching "VID:PID=0403:6014", then throw a particular magic byte string at any such device; that byte string is guaranteed to parse as (relatively) harmless garbage both in the RPC protocol and on the management CLI, and we can guess which one we found by examining the resulting error response. Feh. Please let's do better. _______________________________________________ Tech mailing list Tech@cryptech.is https://lists.cryptech.is/listinfo/tech
