OK, I've done a Fedora kernel rebuild with the stock psmouse.ko getting replaced by
Kyle's BYD driver. In proc/bus/input/devices I now see:
I: Bus=0011 Vendor=0002 Product=0005 Version=0000
N: Name="ImPS/2 BYD TouchPad"
H: Handlers=mouse1 event13
B: KEY=70000 0 0 0 0
Module insertion produces this in the system log:
Mar 7 18:39:38 newtoy kernel: input: ImPS/2 BYD TouchPad as /devices/platform/i8042/serio1/input/input20
Well, that's all distinctly better. But I'm still not getting any action from the
touchpad. No tap to click, no cursor movement. It's dead to the world.
Unfortunately this kernel doesn't have an evbug module, I didn't think to put
that in the build config. But then, I wasn't seeing any events from the pad
with the purism kernels either.
The way this pad worked in the first installer, then became erratic, then stopped
altogether makes me wonder if it's a hardware problem.