The first time I "discovered" CEC was when the arrow keys on my TV remote inadvertently navigated the PS3 system menu. I thought I was hallucinating because there was no mechanism for this magic to happen.
I was thrilled when I saw a Reddit comment about this, and it actually worked with my Sony dumb TV + PS5 + Sony RM-VZ320 universal remote.
(I was sad at having to give up my nice PS4 universal remote, and not finding an equivalent for the PS5.)
However, I couldn't find a button on the remote that was the equivalent of pressing a PS5 controller's PS Button, and that's pretty important to the messy PS5 UI. But the TV had menus that could simulate pressing that button. So I upgraded to a Sony RM-VLZ620, which added programmable macro buttons, which I kludged hard to navigate the TV menus. From my notes:
### Programming PS Button
1. SET(Hold 3 seconds, for LED, then keep holding)
2. middle-circle
3. (Release SET)
4. System-Control-1
5. 9, 8, 1
6. Options
7. Up
8. Down, Down, Down, Down
9. middle-circle, middle-circle
10. SET
Note: The **Up** is a timing NOP, since otherwise
the TV usually only sees only 3 Down rather than 4.
I've had this happen a handful of times with my Frame TV and Steam Deck, though it's inconsistent for some reason. It's pretty cool when it works.
The Deck can pretty consistently turn the TV on from standby(/picture mode) and grab the input, but if the TV is completely off (black screen) CEC doesn't work anymore.
