Lost in gray screen
Today I want to solve a problem: my Linux (Manjaro Xfce) machine does not recognize an external projector plugged with an HDMI cable.
First I installed autorandr and it's dependencies to verify how many monitors were detected via xrandr --listmonitors -> only one detected
Then I read old forum topics and Manjaro documentation and found it may be a driver issue. I ran mhwd -l -d to verify which ones are available. Also doable with the UI (Manjaro Settings / Hardware Configuration / Display controller. One was installed on three available. I installed the other two and reboot. Do not do this at home! Because this is where I get a gray screen after Manjaro logo. I thought everything was lost and that I had to install the OS again. Noooo. Nothing on the BIOS helped. But again, thank you internet, someone said to hit Ctrl+Alt+F3 and then I was able to connect with CLI! There I was able to remove the inappropriate video drivers: sudo mhwd -r pci [driver-name]
Second option: use a VGA cable instead.
It works!! A way to learn that VGA uses an analog signal when it's digital for HDMI.
But I'd like to know how to make it work with an HDMI cable.
Another critical problem is that I still can't read DVDs, it makes some weird noise. I opened VLC via CLI (vlc -v) to get access to error logs. A plugin seemed to be missing, I installed it but same issue. I guess it's because I slightly unscrewed the DVD reader when I disassembled my computer and I missed screwing it back correctly.