One of my machines is mostly a spare, loaded with disks. I just run stable Debian on it, and it never fails. When I last rejuvenated it, I just wanted 4 cpu's and an integrated graphics, since I wasn't playing with it. So I got the recommended simple board with an AMD apu processor. This has all the graphics in it, and the board allows the outputs. I had a very old monitor, and just used VGA, and it worked.
Now we had a monitor shuffle, where the kids get the new ones, and I get the last one in line. This had a DVI input, and so I wanted to use it on this machine. Didn't work. Drove me nuts since I also had a bad dvi cable, and another flaky monitor to compare with. Took me forever to find the good cable, and a good monitor, to prove that the board was not putting out on dvi. Blah.
Turns out there is something you have to do in the kernel, and it's all here.
Compile the radeon as a module, since I couldn't get the hard-kernel method to work. That happens lots of times. All working now. The fun of Linux.
On another note, I had a lot of old computers to get rid of, and I wanted to clean the hard drives. On the old-old machines I took a hammer to the disk, and threw out in the garbage-garbage. Now we have electronic recycling and I want to put these out. I assume they something useful with them. I found that my Tails Linux live usb worked great. I just ran 'shred' on the main disk. Supposed to be garbage man proof!