How do you use your controller on the computer?

If you run Windows and your controller is a Xbox 360 controller with a USB interface (either official Microsoft ones or compatible third-party ones), it should work right out of the box unless if your game does not support gamepads. For PS3 controllers, you can use JoyinMotion to install the Sixaxis drivers for your version of Windows and to manage the controller. Once that's done, Windows will see your PS3 controller as a working game controller. If you have a Bluetooth interface available on your computer, you can also enable that feature too as well.

However, if you run Linux, the process is generally easier unless if the kernel that comes with your distribution does not have the kernel drivers you need for your specific controller. Otherwise, it will work. You will need to have at the very least the command-line utility called xboxdrv. Despite the name, this utility will work with PS3 controllers as well. If you plan on using it wirelessly using Bluetooth, you will need a Bluetooth interface on your computer, and the appropriate Bluetooth extensions for your distribution (typically something like BlueZ). Then you also need to pair your controller while your controller is still connected via USB so that your computer will be able to communicate with the controller on Bluetooth.

Once that's done, you can open up a Terminal session and run xboxdrv. In certain case scenariOS the kernel driver may interfere with the OS enumerating the controller in /dev/. To avoid that, add the --detach-kernel-driver option when running it. This option will detach the built-in kernel driver and enable raw input.

In certain games they don't support raw input (e.g. some games that support Xbox 360-style controllers like Risk of Rain), you can enable the --mimic-xpad option.

You can also run xboxdrv in daemon mode (almost equivalent to "running as a service" in Windows).