So⦠the HDMI and OLED use the system āframebuffersā to output video.
on my Pi4
1 fb_ssd1322 is the OLED (fb1)
0 DRM emulated is the HDMI (fb0)
So⦠in the case of enable_tvout, it seems that this does not use the framebuffers? Will need to do more research on that and see what I can find.
FWIW:
enable_tvout (Pi 4B only)
On the Raspberry Pi 4, composite output is disabled by default, due to the way the internal clocks are interrelated and allocated. Because composite video requires a very specific clock, setting that clock to the required speed on the Pi 4 means that other clocks connected to it are detrimentally affected, which slightly slows down the entire system. Since composite video is a less commonly used function, we decided to disable it by default to prevent this system slowdown.