[baertiger]

Hallo,
I set up a system at my raspberryPi 3b+ with Kodi, an Ambilight based on Hyperion and with a Raspi TV HAT for DVB-T working with tvheadend. This works, but it is not very stable, maybe all these tasks are too much for the system.

So I decided to split the tasks: the Rpi3 will carry out the Ambilight with hyperion, and I now want to try a Rpi4b to drive kodi and tvheadend. The rpi4 has 2 HDMI outputs, so it would be nice to get the graphics output duplicate to both HDMI interfaces, one for the TV and one for the rpi3 controlling the Ambilight.

In the cli the raspi duplicates the output per default, if 2 monitors are connected. The X-window, I found out here, also is possible to duplicate.
But if I start kodi, nothing appears at the 2nd screen. So it seems that kodi uses some other graphics driver. Has somebody an idea how it is possible to get the graphics output to both HDMI interfaces.

[baertiger]

Hallo, still no reply,

so I took a look at the source code and found a sourcefile named xbmc-xrandr.c. So xrandr seems to be used by kodi. And a look inside showed me that the commands referenced in the link in my 1st post (xrandr --output <..> --same-as <..>) should be processed.
Is anybody out there who can help me to get the graphics output splitted to both HDMI outputs in Kodi?

[popcornmix]

Kodi is typically built to use gbm rather than x11 on a Pi (x11 introduces a significant overhead when getting pixels on screen).
There is no code in the gbm path to support multiple monitors.

[baertiger]

Kodi is typically built to use gbm rather than x11 on a Pi (x11 introduces a significant overhead when getting pixels on screen).
There is no code in the gbm path to support multiple monitors.

So I thank you for the info and I'll follow this way not anymore.
Do we have here in this forum any possibility to close this thread or mark it as solved?