[BETTER SOLUTION] ..but keeping this post for reference & continuity.
Well.. I finally did the thing. Here's my workaround:
Install the at job utility.
sudo apt install at
Enable the atd scheduling daemon to start on-boot & run it.
sudo systemctl enable --now atd
After connecting your controllers, record the exact name and event handler # of each one.
cat /proc/bus/input/devices
Now record the axis #s, minimums, & maximums of each controller's analog axes. IGNORE ANY AXIS WHERE ITS MINIMUM & MAXIMUM NEGATE EACH OTHER; ITS MIDPOINT IS 0 AND THE AXIS SHOULD BE LEFT ALONE BY THIS WORKAROUND. In the following command, substitute the event# with that of the associated controller.
evdev-joystick --s /dev/input/event#
Create a new udev rule. You may change the name, but leave the numerical prefix & file extension as-is.
sudo nano /etc/udev/rules.d/99-joystick.rules
Add the following code line in the rules file per controller using the
name, axis #s, minimums, & maximums you gathered earlier. You will need to edit the following template at the [BRACKETED ENTRIES]. Notice that before the at command, there is a evdev-joystick command for each axis to override its minimum & maximum to 0. And after the grep command, the original minimums & maximums for each axis are restored. In my controller, I had four analog axes.. so add/remove axes (aka the evdev-joystick commands) as needed for your controller.
SUBSYSTEM=="input", KERNEL=="event*", ACTION=="add", ATTRS{name}=="[EXACT CONTROLLER NAME]", RUN+="/bin/bash -c \"evdev-joystick --e %E{DEVNAME} --a [1st AXIS #] --minimum 0 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a [2nd AXIS #] --minimum 0 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a [3rd AXIS #] --minimum 0 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a [4th AXIS #] --minimum 0 --maximum 0 ; at -M now <<< 'timeout 30s evtest %E{DEVNAME} | grep -m 1 '\''time .*'\'' ; evdev-joystick --e %E{DEVNAME} --a [1st AXIS #] --minimum [1st AXIS MIN] --maximum [1st AXIS MAX]; evdev-joystick --e %E{DEVNAME} --a [2nd AXIS #] --minimum [2nd AXIS MIN] --maximum [2nd AXIS MAX] ; evdev-joystick --e %E{DEVNAME} --a [3rd AXIS #] --minimum [3rd AXIS MIN] --maximum [3rd AXIS MAX] ; evdev-joystick --e %E{DEVNAME} --a [4th AXIS #] --minimum [4th AXIS MIN] --maximum [4th AXIS MAX]'\""
If you haven't already, follow the previous step for your remaining controllers as new code lines. Then Ctrl-X to exit, Y to save, Enter to confirm. Here is my finished udev rule file for comparison (I didn't need to override the minimums since mine were already 0, so you'll notice them missing from my evdev-joystick commands):
SUBSYSTEM=="input", KERNEL=="event*", ACTION=="add", ATTRS{name}=="Logitech Logitech Cordless RumblePad 2", RUN+="/bin/bash -c \"evdev-joystick --e %E{DEVNAME} --a 0 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 1 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 2 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 5 --maximum 0 ; at -M now <<< 'timeout 30s evtest %E{DEVNAME} | grep -m 1 '\''time .*'\'' ; evdev-joystick --e %E{DEVNAME} --a 0 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 1 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 2 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 5 --maximum 255'\""
SUBSYSTEM=="input", KERNEL=="event*", ACTION=="add", ATTRS{name}=="8Bitdo SF30 Pro", RUN+="/bin/bash -c \"evdev-joystick --e %E{DEVNAME} --a 0 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 1 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 2 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 5 --maximum 0 ; at -M now <<< 'timeout 30s evtest %E{DEVNAME} | grep -m 1 '\''time .*'\'' ; evdev-joystick --e %E{DEVNAME} --a 0 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 1 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 2 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 5 --maximum 255'\""
SUBSYSTEM=="input", KERNEL=="event*", ACTION=="add", ATTRS{name}=="8Bitdo SN30 Pro", RUN+="/bin/bash -c \"evdev-joystick --e %E{DEVNAME} --a 0 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 1 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 2 --maximum 0 ; evdev-joystick --e %E{DEVNAME} --a 5 --maximum 0 ; at -M now <<< 'timeout 30s evtest %E{DEVNAME} | grep -m 1 '\''time .*'\'' ; evdev-joystick --e %E{DEVNAME} --a 0 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 1 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 2 --maximum 255 ; evdev-joystick --e %E{DEVNAME} --a 5 --maximum 255'\""
Reload the udev interface to take on the new rule file.
sudo udevadm control --reload
Reconnect your controllers.. or reboot to force reconnection.
sudo reboot
This workaround was inspired by my previous tests, where I noticed the "Northwest" issue (responsible for the selection jumps) not affecting controllers whose analog axes are using 0 as a midpoint.
So upon first connection of a controller, the new udev rule will override the min/max of any offending axis to 0/0.. thereby forcing 0 as the axis's midpoint. Then, an asynchronous at job is created to await for any button-press on the controller. Once that happens (or the timeout expires), the original min/max value of the controller's axes will immediately restore.. but not after your button-press took action AND without any selection jump! :-D
Important notes:
The workaround is meant to avoid the selection jump on first input of a connected controller IN EMULATION STATION. If you manage to (re)connect it during gameplay, the running emulator may halt or render control unresponsive until it's restarted.
I set the timeout for button-press monitoring to 30s.. partly because you may need a moment to press something after connection.. partly because it's a way to avoid accumulating jobs in the at queue by not waiting indefinitely. If the selection jumps are still happening, press something sooner! ...or you can increase the timeout in the udev rule. But I wouldn't make it higher than 60s.
Otherwise, enjoy your better RetroPie experience everyone!
