Ok, so I've unpacked the ivtv source distributed w/ KM, and patched the drivers/ivtv-cards.c file to have device 0x0003 be recognized as a PVR-150 instead of a 250.

However, no sooner do I do that than a new ivtv is released, noting in the changelog "better detection of PVR-150/-250".

Now, the filename in the /usr/src directory for the ivtv source has a suffix of -pvr150.tar.bz2. Does this mean that this source is customized somehow for the KM distribution? And, if the detection problem recurrs, would it stop me from upgrading to this newer ivtv version?

I don't know if there is anything special about the ivtv source in /usr/src/ (I don't think there is)
- but I can tell you that going back and forth between ivtv versions is not a big deal, provided
they compile on your system. And from a some of things that I have read, you may have to
upgrade your kernel to get ivtv-0.6.0 to compile cleanly on R5B7.

tip..

back up /lib/modules/'uname -r'/ivtv before you install the modules, and that way if you
would like to change to other version of ivtv - just copy them back into place and reboot.

you can switch back and forth as often as you like..