Hi,
I follow this thread for some time trying to keep up with all the work/solutions when i will have time to do this.
There is one thing which is not clear for me : who is setting the correct resolution? Is it done by script before launching the emu (libretro core,...) or are you setting the timings and then when the emu ask for a particular resolution, the system changes accordingly (like emu, i.e. mame with autoswitch res, on a PC with soft15khz for example)?
If this is the first solution, how is the resolution modification during game execution is taken into account?
Of course, imho, the second solution seems to be the best one, but perhaps there is some limitation from the emu themselves.
Anyway, keep up the good work, it will be amazing to have a simple 15khz RGB output on the PI!