This article explains a setup I made for our family vacation place, I wanted to turn an old laptop (a Dell Vostro 1500 from 2008) into a retrogaming station. That's actually easy to do, but I wanted to make it "childproof" so it will always work even if we let children alone with the laptop for a moment, that part was way harder.
This is not a tutorial explaining everything from A to Z, but mostly what worked / didn't work from my experimentation.
First step is to pick an operating system. I wanted to use Alpine, with the persistent mode I described last week, this would allow having nothing persistent except the ROMs files. Unfortunately, the packages for Retroarch on Alpine were missing the cores I wanted, so I dropped Alpine. A retroarch core is the library required to emulate a given platform/console.
Then, I wanted to give FreeBSD a try before switching to a more standard Linux system (Alpine uses the libc musl which makes it "non-standard" for my use case). The setup was complicated as FreeBSD barely do anything by itself at install time, but after I got a working desktop, Retroarch had an issue, I couldn't launch any game even though the cores were loaded. I can't explain why this wasn't working, everything seemed fine. On top of this issue, game pad support have been really random, so I gave up.
Finally, I installed Debian 12 using the netinstall ISO, and without installing any desktop and graphical server like X or Wayland, just a bare Debian.
To achieve a more children-proof environment, I decided to run Retroarch directly from a TTY, without a graphical server.
This removes a lot of issues:
In addition to all the benefits listed above, this also reduces the emulation latency, and makes the system lighter by not having to render through X/Wayland. I had to install the retroarch package and some GL / vulkan / mesa / sdl2 related packages to have it working.
One major painful issue I had was to figure a way to start retroarch in tty1 at boot. Actually, this is really hard, especially since it must start under a dbus session to have all features enabled.
My solution is a hack, but good enough for the use case. I overrode the getty@tty1 service to automatically log in the user, and modified the user `~/.bashrc` file to exec retroarch. If retroarch quits, the tty1 would be reset and retroarch started again, and you can't escape it.
I can't describe all the tweaks I did in retroarch, some were for pure enhancement, some for "hardening". Here is a list of things I changed:
In addition to all of that, there is a lovely kiosk mode. This basically just allow you to password protect all the settings in Retroarch, once you are done with the configuration, enable the kiosk mode, nothing can be changed (except putting a ROM in favorite).
I configured a few more extra things to make the experience more children proof.
Grub can be a major issue if a children boots up the laptop but press a key at grub time. Just set `GRUB_TIMEOUT=0` to disable the menu prompt, it will directly start into Debian.
The computer doesn't need to connect to any network, so I disabled all the services related to network, this reduced the boot time by a few seconds, and will prevent anything weird from happening.
It may be wise to lock the bios, so in case you have children who know how to boot something on a computer, they wouldn't even be able to do that. This also prevent mistakes in the bios, better be careful. Don't lose that password.
If you want your gaming console to have this extra thing that will turn the boring and scary boot process text into something cool, you can use Plymouth.
I found a nice splash screen featuring Optimus head from Transformers while the system is booting, this looks pretty cool! And surely, this will give the system some charm and persona compared to systemd boot process. This delays the boot by a few seconds though.
Retroarch is a fantastic software for emulation, and you can even run it from a TTY for lower latency. Its controller mapping is really smart, you have to configure each controller against some kind of "reference" controller, and then each core will have a map from the reference controller to convert into the console controller you are emulating. This mean you don't have to map your controller for each console, just once.
Doing a children proof kiosk computer wasn't easy, I'm sure there is room for improvement, but I'm happy that I turned a 15 years old laptop into something useful that will bring joy for kids, and memories for adults, without them fearing that the system will be damaged by kids (except physical damage but hey, I won't put the thing in a box).
Now, I have to do some paint job for the laptop behind-the-screen part to look bright and shiny :)