Pi4 second HDMI output not displaying Emulation Station (but does display Pi generated graphics)

[Red_Trev]

Hi all,

I have a I have a Pi 4 with 8GB of RAM, with official power supply & micro HDMI cable. Used the official Raspberry Pi Imager software to flash a micro SD card with latest version of Retropie.

As I use an old model TV , I have tweaked the config.txt file to the following settings:

hdmi_force_hotplug=1
config_hdmi_boost=7
hdmi_group=2
hdmi_mode=16
disable_overscan=0
overscan_left=0
overscan_right=0
overscan_top=0
overscan_bottom=0

I wish to record my game play so I got a new cable for the second micro HDMI output & connected it to a HDMI to USB Video Capture Card (see below pic). I then plugged this into my laptop running OBS & selected the USB input as a source.

When I first turned ON the Pi there was nothing coming through to the laptop. I swapped the new cable onto the first micro HDMI output and the Emulation Station video/ sound came through perfectly.

I Googled the problem and discovered that the config.txt file values can be tweaked for both outputs (https://www.raspberrypi.org/documentation/configuration/config-txt/conditional.md) therefore I stated the same settings for both outputs (i.e.)

hdmi_force_hotplug:0=1
hdmi_force_hotplug:1=1
config_hdmi_boost:0=7
config_hdmi_boost:1=7
etc .....

This time when I turned ON the Pi, the first HDMI output displayed as normal . The second HDMI output showed the rainbow start up image, then the booting up commands scrolling down the screen, then a black screen. It did not show the Retropie logo or the Emulation Station logo either.

However, when I opened a game the pre-launch grey pop up that displays "Launching GAME X (EMULATOR Y) Press a button to configure" does appear on the second HDMI output & stays there until the game is exited.

I swapped around the cables in the outputs & the image worked perfectly, so its not the cable / USB Video Capture Card / OBS.
It seems to be some missing setting on the second HDMI output, so that it only displays graphics generated by the Raspberry Pi itself rather than RetroPie / Emulation Station.

All help is appreciated !!

[porkyshmorky]

@red_trev I’m currently in the exact same situation. Is displaying emulation station, as well as all emulators run through it, on the second display even possible? Sorry for replying to this old post, but I have searched far and wide without coming across any solutions (that doesn’t require x session, xrandr etc...).

[ItzRayningTTV]

@red_trev The only thing i can find as of right now is Displaying a single image through secondary port for like a digital marquee on a an arcade but im in the same exact boat if you have never heard of ETA prime he has awesome content and is very informative...
Video here ------>

[iceblink]

framebuffer_priority=7

was the only option I needed in config.txt to get emulation station to work from hdmi 1.

(I needed to use this as the fat micro hdmi adapter I was using pressed against the usb-c power connector)

These are the only options I have set in config.txt (audio and video on second hdmi port 1 work fine in emulation station)

framebuffer_priority=7

#  OVERCLOCK SETTINGS
arm_freq=1800  # CPU Frequency
gpu_freq=600   # GPU Frequency
over_voltage=2 # Electric power sent to CPU / GPU (4 = 1.3V)

dtparam=audio=on

# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2