Hello,

I haven't done a thorough bisection of kernel revisions, but moving from kernel 4.17.19 to 4.18.6 results in mythtv being unable to tune in any channel with a pic hdtv 5500 tuner (cx88 based device with an LG frontend). I get an error back from the channel scanner about not being able to measure signal strength and getting back an error unknown (errno 254).

I was able to use dvbtools with get-atsc to get a channel, but I don't think any of the forward error correction was applied to it.

Let me know if you need more details.