TechnologyResearcher
Posts: 1
Joined: Wed Jun 24, 2020 6:47 am

resolution stuck with rpi 4 [UBUNTU]

Wed Jun 24, 2020 6:53 am

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
Posts: 22
Joined: Thu Feb 14, 2019 10:08 pm

Re: resolution stuck with rpi 4 [UBUNTU]

Tue Jun 30, 2020 1:01 am

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
Posts: 42
Joined: Mon Dec 30, 2013 9:20 am

Re: resolution stuck with rpi 4 [UBUNTU]

Tue Jun 30, 2020 7:09 am

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.

User avatar
waveform80
Posts: 359
Joined: Mon Sep 23, 2013 1:28 pm
Location: Manchester, UK
Contact: Website Twitter

Re: resolution stuck with rpi 4 [UBUNTU]

Thu Jul 02, 2020 2:09 pm

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).
Author of / contributor to a few pi related things (picamera, Sense HAT emulator, gpio-zero, piwheels, etc.), and currently a software engineer at Canonical responsible for Ubuntu Server and Core on the Raspberry Pi.

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