You can check like this:
- To make sure reboot your machine,
- open up a terminal, and do tail -f /var/log/messages
- fire up myth and do a channel scan
-> If you're in the same position, you will see a message saying that it can't load the firmware
This is what put my attention back to the Karmic link. - If so, something's wrong with your firmware.
Be sure to have a proper look at the link to the Karmic and HVR-4000 thread.
Do the md5sum check with your firmware sitting at /lib/firmware and make sure the md5sum is the same as on the Ubuntu forum. Mine was different - so I redownloaded and double checked.
I'm not an expert on this, but I'm fairly sure that Kaffeine does not need the firmware - don't ask me why. (I'd sure like to understand the difference though!!)
For MythTV there are 2 criteria that need to be fullfilled:
- v4l-dvb drivers need to be loaded (dmesg will list your card as HVR-4000)
- the firmware must load
Also for scanning I found that depending on what country you choose, Myth skips or limits channels, e.g. I'm in Belgium and scanning using France as a country works, but using Austria fails.
I have also gone back to somewhere 25/11/09 in the v4l-dvb repo. If the above does not help, let me know, I'll dig up my emacs install log and post the exact repo to clone.
Hope this helps!