Keyboard/Mouse not working in GUI with Ryzen 3200G/Vega 8

I bought an ASRock DESKMINI A300W and installed a Ryzen 3200G/Vega 8 in it yesterday. I'm trying to install Manjaro Cinnamon on it. I almost was able to do this, but ran into a hiccup.

What I've done so far

  1. Cinnamon install CD didn't boot to GUI after trying various options so switched to Manjaro Architect installer.
  2. I completed the install on Manjaro Architect, installing a variety of kernels since I knew some might workable and some might not. I have 4.19, 4.4, 5.1, 5.2, 5.3 right now
  3. 4.19 / 4.4 kernels will not start lightdm no matter what I've tried. Xorg.0.log just shows it going through all the various modules from ati to radeon to fbdev/etc. and it seems to be failing each and then drops out entirely at the end.
  4. 5.2 kernel gets all the way to lightdm, and it looks perfect, but keyboard and mouse both do not work. Same occurs with 5.3 and 5.1. I can't even use the keyboard to switch out to a terminal.

I'm just trying to figure out what to try next. What's the easiest way for me to get to terminal in 5.1 and bypass lightdm loading automatically? I have read about editing the startup for grub but none of the posts I've seen this mentioned on matches with what I see in the configuration so I'm not sure exactly how to change it.

You can get to grub screen on boot. i believe it's holding down shift key?
Press e to edit. Then take out quiet and put a 3. F10 to boot.
This is not a permanent change. It's only for this boot.

This will put you at a prompt. Might want to make sure you're completely updated.
sudo pacman-mirrors -f5 && sudo pacman -Syyu.
Then reboot and see if it's working.

Thanks, I finally figured out the "3" earlier today. Other posts I was reading from the past had set to put /bin/sh or /bin/bash where the 3 went, and that didn't work but thankfully the 3 did.

The other issue I had was because i mistakenly had installed catalyst, and then I removed it but I didn't realize that I had to reinstall some other things to get everything working, specifically xf86-input-keyboard, xf86-input-mouse, and xf86-input-libinput was what it took to get the keyboard and mouse working.

I have a little flickering every few minutes I'm now trying to get rid of. I've removed xf86-video-intel and that seems to have made it happen a lot less but it still happens occasionally, but not often enough to be a real pain.

I'm going to try to remove some other unnecessary video-* stuff to see if that also helps as someone recommended it on linuxquestions just now.

Thanks for the response!

Be careful.
Don't install video drivers through pamac or whatever.
Use Manjaro Settings Manager.
It's a front-end for mhwd. It handles video drivers and kernels very well.

Here's the wiki on how to configure your graphics card. I'd be careful using advice from around the web. There's some specific ways to do things in Manjaro.