On 4/5/22 08:51, Michael Hennebry wrote:
On Tue, 5 Apr 2022, Samuel Sieb wrote:
Install "monitor-edid" and run it. See if it sees the correct monitor resolutions.
$ monitor-edid you must be root to run this program
That is strange. It worked for me as a user.
$ sudo monitor-edid mmap /dev/mem: Permission denied $ sudo sh sh-5.1# whoami root sh-5.1# monitor-edid mmap /dev/mem: Permission denied sh-5.1# ls -l /dev/mem crw-r-----. 1 root kmem 1, 1 Apr 5 02:58 /dev/mem sh-5.1#
I wonder if it's because you have secure boot enabled.
Had it worked, would the screen have changed instantly?
No, that just lists the available modes of the monitor. I was trying to check if the EDID was working properly.
Another way that might work with secure boot enabled is to use "decode-edid" instead. Install it, then run "find /sys -name edid". On my system, that gives me: /sys/devices/pci0000:00/0000:00:08.1/0000:05:00.0/drm/card0/card0-HDMI-A-1/edid /sys/devices/pci0000:00/0000:00:08.1/0000:05:00.0/drm/card0/card0-HDMI-A-2/edid /sys/devices/pci0000:00/0000:00:08.1/0000:05:00.0/drm/card0/card0-DP-1/edid
My monitor is connected to "HDMI-A-2". If you don't know which one, then just cat each one until you get a bunch of garbage on the terminal. Then run the following, but replace with the right path.
edid-decode < /sys/devices/pci0000:00/0000:00:08.1/0000:05:00.0/drm/card0/card0-HDMI-A-2/edid