I'm trying to use multiple sega saturn controllers on a single parallel port by the db9 driver. The adapter uses a dual port input and a single printer output. From my testing it works with only a single controller connected. Does not work with 2 controllers. Also does not work when using a multitap (a device to connect 6 controllers to one single input). The adapter uses the scheme from Direct Pad Pro. It's not listed in the kernel documentation https://www.kernel.org/doc/html/latest/input/devices/joystick-parport.html But I found it looking in the source https://github.com/torvalds/linux/blob/master/drivers/input/joystick/db9.c In the source there's two parameters for the saturn DPP: DB9_SATURN_DPP and DB9_SATURN_DPP_2 From what I could understand it's for using one or two devices connected to the lpt port. Looks like it should support 12 controllers by using 2 multitap adapters. With this command: modprobe -v db9 dev=0,11 This way a single controller works. Only on the first adapter port. Multitap does not work. With: modprobe -v db9 dev=0,12 Nothing works No errors reported on dmesg. There's also a DB9_SATURN_PAD db9 parameter but I think it's for another adapter. The adapter works. Wiring is correct. It works fine on windows on the same hardware. I don't know when it stopped working in linux as it's my first time trying to use it. Tested on ubuntu 20.10 and on a libreelec distro.