Gamepad not recognized as joystick

[Afiefh]

I recently brought out my old bluetooth HID gamepad (iPEGA PG-9053) and was surprised to find that I didn't get any input in SDL games, though I know it used to work with older versions of Ubuntu (approximately 14.04 I think). KDE's "input devices" configuration would be able to perfectly read from /dev/input/js0 but many games failed to get any input from the gamepad.

It turns out that the reason for this is that the event devices (/dev/input/event*) were not readable for the default Ubuntu user (crw-rw----, group=input).

It seems that only devices that are marked as Joysticks will have global read permission set for them. This means that apparently my humble gamepad was not detected as such. The following is the udev info for my gamepad:

$ udevadm info --name=input/event21
P: /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5.3/2-1.5.3:1.0/bluetooth/hci0/hci0:12/0005:1949:0402.000A/input/input31/event21
N: input/event21
E: BACKSPACE=guess
E: DEVNAME=/dev/input/event21
E: DEVPATH=/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5.3/2-1.5.3:1.0/bluetooth/hci0/hci0:12/0005:1949:0402.000A/input/input31/event21
E: ID_BUS=bluetooth
E: ID_INPUT=1
E: ID_INPUT_KEY=1
E: ID_INPUT_KEYBOARD=1
E: ID_INPUT_MOUSE=1
E: LIBINPUT_DEVICE_GROUP=5/1949/402/11b:00:1a:7d:0a:ba:28
E: MAJOR=13
E: MINOR=85
E: SUBSYSTEM=input
E: USEC_INITIALIZED=7821377694
E: XKBLAYOUT=us,il
E: XKBMODEL=pc105
E: XKBOPTIONS=grp:alt_shift_toggle,grp_led:scroll
E: XKBVARIANT=,

$ udevadm test-builtin input_id /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5.3/2-1.5.3:1.0/bluetooth/hci0/hci0:12/0005:1949:0402.000A/input/input31/event21
calling: test-builtin
=== trie on-disk ===
tool version: 231
file size: 7291492 bytes
header size 80 bytes
strings 1819268 bytes
nodes 5472144 bytes
Load module index
Found container virtualization none
timestamp of '/etc/systemd/network' changed
timestamp of '/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 12001f
capabilities/ev decoded bit map:
  bit 0: 000000000012001F
capabilities/abs raw kernel attribute: 30627
capabilities/abs decoded bit map:
  bit 0: 0000000000030627
capabilities/rel raw kernel attribute: 103
capabilities/rel decoded bit map:
  bit 0: 0000000000000103
capabilities/key raw kernel attribute: 7fff000000070000 1000000000007 ff9f307ac1405fff febeffdfffefffff fffffffffffffffe
capabilities/key decoded bit map:
  bit 0: FFFFFFFFFFFFFFFE
  bit 64: FEBEFFDFFFEFFFFF
  bit 128: FF9F307AC1405FFF
  bit 192: 0001000000000007
  bit 256: 7FFF000000070000
properties raw kernel attribute: 0
properties decoded bit map:
ID_INPUT_MOUSE=1
test_key: checking bit block 0 for any keys; found=1
test_key: checking bit block 64 for any keys; found=1
test_key: checking bit block 128 for any keys; found=1
test_key: checking bit block 192 for any keys; found=1
ID_INPUT_KEY=1
ID_INPUT_KEYBOARD=1
Unload module index
Unloaded link configuration context.

There is a similar bug for a different peripheral here: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1332444