Right. Diary time so I keep on top of this... I'm getting two lots of errors in syslog:
dvb_usb: disagrees about version of symbol dvb_dmxdev_init
dvb_usb: Unknown symbol dvb_dmxdev_init (err -22)
From hunting around, the first effectively means that the module is intended for a different kernel version. The second means that the module has a dependency on a symbol (the same one) that should be in the kernel, but isn't - the kernel was compiled with it missing and/or it's no use because of that version issue. Both mean a reconfigure-and-recompile of the kernel.
Now, my DVB-T card is supported in all even vaguely-recent kernels, but all this suggests that I still need to recompile it specifically for this one. My suspicion is that dkms is recompiling that bit of the "normal" kernel build (v4l), but leaving out the support for this card, instead relying on the currently-compiled version... which it doesn't like.
Soooo... I can think of three options:
1. Break the yavdr package and manually insert the driver code into the right place (/usr/src/linux-media-tbs-0~20111123.111118.1~oneiric) - but that will get promptly eaten at the next ppa update (presumably triggered by TBS updating their drivers, but not necessarily looking at the dates - TBS' current version is 120814 - so 14/Aug - versus the ppa date of 23/Nov last year - so such an update may never happen or be intermittent). Sounds like a bad idea.
2. Create my own dkms directory for these drivers (installed into /usr/src) so that it compiles alongside the TBS files. That'd work, but I'm still dependent on the yavdr versions.
3. Abandon the yavdr dkms package now I can see what it's doing, and move the full TBS v4l tree (which includes all the right drivers) into /usr/src along with a hacked version of the dkms.conf from the yavdr ppa. I can then uninstall the yavdr TBS package.
All options would give me the DiBcom7000 drivers *and* the TBS drivers - but the third option allows me to update those drivers when TBS release a new version (indeed, I can build those drivers in now since I'd control that dkms package). So that's the route I'm going to investigate...
Update as I get anywhere.