So I just tried to connect up to my ancient Soekris firewall's serial console to try to bisect a problem where it stopped booting in 4.20, and found I couldn't. minicom says: minicom: cannot open /dev/ttyUSB0: Input/output error and in the dmesg we see [705576.028170] pl2303 ttyUSB0: failed to submit interrupt urb: -28 Booting to 4.19, everything works fine. (A random GalliumOS Chromebook running 4.9.4 works fine too, not that that confirmation is terribly useful.) This is an extremely preliminary report in case it's instantly obvious what's going on: I'll do enough investigation to produce an actually useful bug report, including bisecting this, after I've bisected the *other* non-booting bug, but that might not be until next weekend. (All this for a firewall I was trying to decommission! bah :) )
