Sorry for the novice question. My app depends on the uio_pruss module being loaded before it's launched. It runs as a daemon, launched from a script in /etc/init.d. I'm not familiar enough with the dependency-based init to know if I can put a dependency on a kernel module. I'm seeing in the log at boot that a call to pru_init() fails, but if I run it later, it succeeds. That tells me that uio_pruss isn't loaded yet.
Anyway, I tried searching for a way to set up a dependency on a kernel module, and couldn't find one. But I did find kmod, and I set up a dependency on that, then I put uio_pruss in /etc/modules, and that seemed to fix it.
The thing that I don't understand is how uio_pruss was getting loaded in the first place (before I listed it in /etc/modules). It was available when executing my app after login without me doing anything explicit.