Not a bug.

You're trying to run a command to control an Intel GPU-specific parameter on an xorg display, while rpi4 uses a VideoCore GPU on Wayland.

The correct way to adjust such parameters on rpi4 is in /boot/config.txt

Try setting hdmi_pixel_encoding=2

For more info see https://elinux.org/RPiconfig

@n2qz
You have the wrong information, hdmi_pixel_encoding is a deprecated option for the deprecated fkms driver, which is now unsupported. "Broadcast RGB Full" this toggle option was backported into the kernel by the raspberry command a long time ago and it works. For x11 this is xrandr --output HDMI-1 --set "Broadcast RGB" "Full", and for wayland, you can use modetest -M vc4 -w 32:"Output format":3 I tested modetest on wayland and it works too, but only when I add this command to .profile

You tested it with modetest on Batocera?

I tested modetest on RaspberryOS and Ubuntu with Wayland. As I wrote in the first post, the Batocera distribution for raspberry pi lacks the necessary packages. modetest is part of libdrm-tests

Install the build from this drive: https://drive.google.com/drive/folders/1OaxfQoMTO08jVlKbaMM-iGpo1sXnIj4P?usp=drive_link

Put your modetest commands in /boot/preshare.sh (remember to remount /boot as read-write first), then reboot.

Here's what I tested with, I can observe that the values are changed but I don't notice any change in the way the display appears on my system:

[root@adric-wlan0 /boot]# cat /boot/preshare.sh
modetest -M vc4 -w 32:"Broadcast RGB":1
modetest -M vc4 -w 32:"Output format":1

Thanks, modetest works, it switches to full mode. But in this build there is a problem not related to modetest. For some reason the whole interface does not work smoothly, as if in 20-25fps (although according to the frame counter more). Compared with version 40 and there everything is fine.

Thanks for the confirmation. I'll get the modetest binary included in either v41 or v42, depending on when our next buildroot bump occurs.

The other issue is completely separate, and was already reported. You may want to chime in on the relevant report.

This is relevant not only for raspberry pi 4, but for all models running on kms driver. At least libdrm-tests should be enabled for raspberry pi 5 as well.