STM32MP157C-DK2 HDMI Output of Xorg


I’ve been working on getting a kiosk-style application running on the STM32MP157C-DK2 development board running Debian (thank you to @RobertCNelson for the tutorial!). Coming from RPi, I’m slowly building my knowledge of the lower levels of the OS as I chip away at each problem I encounter!

I’ve installed X11 (Xorg?) and can now launch my armhf Electron application on the DK2’s display and would like to utilise my 10" display via the DK2’s HDMI port for easier development - but notice that nothing happens when it’s connected. I suspect that I am missing a driver and/or some configuration (perhaps in /etc/X11/xorg.conf?).

How do I output my X11 session over HDMI on the STM32MP157-DK2? I don’t need the onboard display at the same time, but would be nice to switch between them via configuration.

I’ve done some research online (here, and here)and see mention of:

  • Adding video=DSI-1:d to the console line in extlinux.conf driver (didn’t work for me, still no HDMI output - only onboard LCD)
  • Installing driver xf86-video-armada (is this related to xserver-xorg-video-armada-etnaviv?) and configuring it somehow

Would really appreciate any assistance on this as i’m not quite sure how to proceed. Lots of ST’s documentation relates to their Yocto builds and the source on Github for OpenSTLinux is a little difficult for me to decipher. If I’m even looking in the right place.

Thank you!

My steps to reach this point:

  • Built debian image (not using Ubuntu as desktop is enabled by xorg and extremely slow)

  • Install xorg

  • Install read-edid xserver-xorg-video-fbdev x11-xserver-utils

  • Create xorg.conf file in /etc/X11/xorg.conf (as per Debian: Getting Started with the BeagleBone Black)

  • Install chromium (for testing - not essential)

  • Install test-application deb

  • Run startx (notice font change as different terminal?)

  • Run test-application or chromium and see it open onscreen!