Back/Home buttons not working when paired over BT to Legends Arcade control deck

[mrhector]

I have an Atgames Legends Ultimate arcade v1.1. The control deck has the options to pair to external devices via OTG or Bluetooth. Previously when paired over BT all the buttons would map like a controller including the back button and the home button.

This was always the case when you connected via OTG but bluetooth would work. Now I noticed that even over bluetooth the Back and Home buttons simply don't register in the Test Input screen.

https://wagnerstechtalk.com/steamdeck/#Connect_to_ALU_USB

On the Steamdeck the controller shows up as
Device Support ID: 45e-40-2e35e (0x045e,0x0040)

[mrhector]

After some digging found out the Back and Home buttons are being detected as keyboard media key codex XF86Back and XF86Home

[mrhector]

So figured out the issue. Looks like each player on the control deck is detected as 3 devices, one is detected as joystick, one as a keyboard, and the trackball as a mouse. I've looked up similar problems and folks talk about setting up udev rules to either change the attributes to make it a joystick or block the device and have fall through and detect properly. Been looking at the Arch linux gamepad section but not sure what would be the best solution.

(130)(deck@steamdeck ~)$ sudo evtest
[sudo] password for deck:
No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0: Power Button
/dev/input/event1: Lid Switch
/dev/input/event10: HD-Audio Generic HDMI/DP,pcm=3
/dev/input/event11: HD-Audio Generic HDMI/DP,pcm=8
/dev/input/event12: HD-Audio Generic HDMI/DP,pcm=9
/dev/input/event13: FTS3528:00 2808:1015
/dev/input/event14: FTS3528:00 2808:1015 UNKNOWN
/dev/input/event15: acp5x Headset Jack
/dev/input/event16: Control deck-P2 Mouse
/dev/input/event17: Control deck-P2 Consumer Control
/dev/input/event18: Control deck-P2
/dev/input/event19: Microsoft X-Box 360 pad 0
/dev/input/event2: Power Button
/dev/input/event20: Control deck-P1 Mouse
/dev/input/event21: Control deck-P1 Consumer Control
/dev/input/event22: Control deck-P1
/dev/input/event23: Microsoft X-Box 360 pad 1
/dev/input/event24: Microsoft X-Box 360 pad 2
/dev/input/event3: Video Bus
/dev/input/event4: HD-Audio Generic HDMI/DP,pcm=7
/dev/input/event5: Valve Software Steam Deck Controller
/dev/input/event6: AT Translated Set 2 keyboard
/dev/input/event7: Valve Software Steam Deck Controller
/dev/input/event8: Logitech K400 Plus
/dev/input/event9: PC Speaker
Select the device event number [0-24]:


(130)(deck@steamdeck ~)$ sudo udevadm info --query=all --name=input/event21
P: /devices/virtual/misc/uhid/0005:045E:0040.0021/input/input107/event21
M: event21
R: 21
U: input
D: c 13:85
N: input/event21
L: 0
E: DEVPATH=/devices/virtual/misc/uhid/0005:045E:0040.0021/input/input107/event21
E: DEVNAME=/dev/input/event21
E: MAJOR=13
E: MINOR=85
E: SUBSYSTEM=input
E: USEC_INITIALIZED=13586009816
E: ID_INPUT=1
E: ID_INPUT_KEY=1
E: ID_BUS=bluetooth
E: LIBINPUT_DEVICE_GROUP=5/45e/40:ec:2e:98:cf:2d:2c
E: TAGS=:power-switch:
E: CURRENT_TAGS=:power-switch:


(1)(deck@steamdeck ~)$ sudo udevadm info --query=all --name=input/event22
P: /devices/virtual/misc/uhid/0005:045E:0040.0021/input/input108/event22
M: event22
R: 22
U: input
D: c 13:86
N: input/event22
L: 0
E: DEVPATH=/devices/virtual/misc/uhid/0005:045E:0040.0021/input/input108/event22
E: DEVNAME=/dev/input/event22
E: MAJOR=13
E: MINOR=86
E: SUBSYSTEM=input
E: USEC_INITIALIZED=13586030395
E: ID_INPUT=1
E: ID_INPUT_JOYSTICK=1
E: ID_BUS=bluetooth
E: ID_INPUT_JOYSTICK_INTEGRATION=external
E: LIBINPUT_DEVICE_GROUP=5/45e/40:ec:2e:98:cf:2d:2c
E: TAGS=:uaccess:seat:
E: CURRENT_TAGS=:uaccess:seat:

[mrhector]

The issues sounds similar to this, where a portion of the device is falling back and sending XF86Home and XF86Back events.

https://wiki.archlinux.org/title/Gamepad#Multi-mode_wired_gamepads