The trackpoint sometimes doesn't work when the machine is freshly booted. It always works after resuming from a suspend. A workaround to this problem is to use tpconfig to reset the hardware when the machine is booted; this workaround is incorporated into the below.

Interestingly, one of my colleagues experienced exactly the same problem after booting Windows 2000. So perhaps this problem isn't a Linux problem; it might be a BIOS bug. Since performing a software reset fixes the problem, it might be that the BIOS isn't properly initializing the hardware at boot. Other reports indicate that the trackpoint initializes reliably when an external mouse is plugged in.

I have requested additional information from HP about the trackpoint hardware and hope to use this to fix the problem. If the hardware supports additional features (e.g. push-to-click) it may also be possible to get access to them.