resolution stuck with rpi 4 [UBUNTU]

[TechnologyResearcher]

I seem to be having an issue with the rpi4 to be stuck at same resolution 597x448 4:3.

I have searched google and this forum with sope very usefull solution for this issue but at this point not everything is working.

so i got rpi 4 4GB
os: ubuntu 20.04 headless -> installed gnome-desktop

first issue was having no ui at all so i configured hdmi in usercfg.txt file at /boot/firmware -> working now

for the resolution i have set my hdmi_mode and group and i also found you have a seperate flag for 4k with rpi which is also set.
resolution is still the same.

hdmi is in the gdmi 0 port my tv is 4k resolution so i guess i'll can set the output to 4k aswell

full config now:

hdmi_safe=1

hdmi_force_hotplug=1

hdmi_group=1

hdmi_mode=97

hdmi_enable_4kp60=1

config_hdmi_boost=9

[kazin08]

Rpi4 has 2 video output, so you have to specify from where you want to use, so try this:

in my case i use 1080p and :0 select de HDMI-0
hdmi_safe:0=1
hdmi_group:0=2
hdmi_mode:0=82

And see if you have this parameter in usercfg.txt/config.txt:

dtoverlay=vc4-fkms-v3d

Regards

[PiUser10]

As well as the dtoverlay line you may also need to add the line
disable_overscan=1
to remove the black borders and get access to the full screen resolution.

[waveform80]

As kazin08 has noted, dtoverlay=vc4-fkms-v3d is very important for anyone wanting to attempt running a desktop on Ubuntu. Without this, most desktop environments will have trouble driving the display (or at the very least will be unreliable).