(In reply to comment #14)
> 
> FWIW this is my 24Hz line as shown by xrandr --verbose, maybe yours is
> different?
> 
> 1920x1080 (0x2cd)   74.2MHz +HSync +VSync
>         h: width  1920 start 2558 end 2602 total 2750 skew    0 clock  27.0KHz
>         v: height 1080 start 1084 end 1089 total 1125           clock  24.0Hz
> 

  1920x1080@23.976 (0x5e)   74.2MHz +HSync +VSync *current
        h: width  1920 start 2558 end 2602 total 2750 skew    0 clock   27.0KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   24.0Hz

So identical I'd say.

> Having never used pulse I don't know if it's easy to bypass (assuming you
> are using it),

Nope, direct alsa.