Comment 0 for bug 1530384

I ports Ubuntu touch to LG L90 Dual. When I upgraded my device from 20151218.1 to 20151221 (channel rc-proposed), the touchscreen stopped working. A discussion in IRC with @anpok_ suggesting that it may come from changing input system to libevent.

$ udevadm test-builtin input_id /devices/gpio_keys.70/input/input2/
calling: test-builtin
=== trie on-disk ===
tool version: 219
file size: 6711498 bytes
header size 80 bytes
strings 1721914 bytes
nodes 4989504 bytes
Load module index
Network interface NamePolicy= disabled on kernel command line, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/00-rmnet-kernel.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 3
capabilities/ev decoded bit map:
  bit 0: 00000003
capabilities/abs raw kernel attribute: 0
capabilities/abs decoded bit map:
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 4000000 0 0 0 c0040 0 0 0
capabilities/key decoded bit map:
  bit 0: 00000000
  bit 32: 00000000
  bit 64: 00000000
  bit 96: 000C0040
  bit 128: 00000000
  bit 160: 00000000
  bit 192: 00000000
  bit 224: 04000000
properties raw kernel attribute: 0
properties decoded bit map:
test_key: checking bit block 0 for any keys; found=0
test_key: checking bit block 32 for any keys; found=0
test_key: checking bit block 64 for any keys; found=0
test_key: checking bit block 96 for any keys; found=1
test_key: checking bit block 128 for any keys; found=1
test_key: checking bit block 160 for any keys; found=1
test_key: checking bit block 192 for any keys; found=1
test_key: checking bit block 224 for any keys; found=1
ID_INPUT_KEY=1
Unload module index
Unloaded link configuration context.

$ udevadm test-builtin input_id /devices/virtual/input/input0/
calling: test-builtin
=== trie on-disk ===
tool version: 219
file size: 6711498 bytes
header size 80 bytes
strings 1721914 bytes
nodes 4989504 bytes
Load module index
Network interface NamePolicy= disabled on kernel command line, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/00-rmnet-kernel.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: b
capabilities/ev decoded bit map:
  bit 0: 0000000B
capabilities/abs raw kernel attribute: 6718000 0
capabilities/abs decoded bit map:
  bit 0: 00000000
  bit 32: 06718000
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 400 0 0 2000000 0 1000 40000800 100000 0 10000000 0
capabilities/key decoded bit map:
  bit 0: 00000000
  bit 32: 10000000
  bit 64: 00000000
  bit 96: 00100000
  bit 128: 40000800
  bit 160: 00001000
  bit 192: 00000000
  bit 224: 02000000
  bit 256: 00000000
  bit 288: 00000000
  bit 320: 00000400
properties raw kernel attribute: 0
properties decoded bit map:
test_key: checking bit block 0 for any keys; found=0
test_key: checking bit block 32 for any keys; found=1
test_key: checking bit block 64 for any keys; found=1
test_key: checking bit block 96 for any keys; found=1
test_key: checking bit block 128 for any keys; found=1
test_key: checking bit block 160 for any keys; found=1
test_key: checking bit block 192 for any keys; found=1
test_key: checking bit block 224 for any keys; found=1
ID_INPUT_KEY=1
Unload module index
Unloaded link configuration context.

$ udevadm test-builtin input_id /devices/virtual/input/input1/
calling: test-builtin
=== trie on-disk ===
tool version: 219
file size: 6711498 bytes
header size 80 bytes
strings 1721914 bytes
nodes 4989504 bytes
Load module index
Network interface NamePolicy= disabled on kernel command line, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/00-rmnet-kernel.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 3
capabilities/ev decoded bit map:
  bit 0: 00000003
capabilities/abs raw kernel attribute: 0
capabilities/abs decoded bit map:
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 100000 0 0 0
capabilities/key decoded bit map:
  bit 0: 00000000
  bit 32: 00000000
  bit 64: 00000000
  bit 96: 00100000
properties raw kernel attribute: 10
properties decoded bit map:
  bit 0: 00000010
test_key: checking bit block 0 for any keys; found=0
test_key: checking bit block 32 for any keys; found=0
test_key: checking bit block 64 for any keys; found=0
test_key: checking bit block 96 for any keys; found=1
test_key: checking bit block 128 for any keys; found=1
test_key: checking bit block 160 for any keys; found=1
test_key: checking bit block 192 for any keys; found=1
test_key: checking bit block 224 for any keys; found=1
ID_INPUT_KEY=1
Unload module index
Unloaded link configuration context.

$ udevadm test-builtin input_id /devices/sound-9302.42/sound/card0/input3/
calling: test-builtin
=== trie on-disk ===
tool version: 219
file size: 6711498 bytes
header size 80 bytes
strings 1721914 bytes
nodes 4989504 bytes
Load module index
Network interface NamePolicy= disabled on kernel command line, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/00-rmnet-kernel.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 3
capabilities/ev decoded bit map:
  bit 0: 00000003
capabilities/abs raw kernel attribute: 0
capabilities/abs decoded bit map:
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 7a 4 0 0 0 c0000 0 0 0
capabilities/key decoded bit map:
  bit 0: 00000000
  bit 32: 00000000
  bit 64: 00000000
  bit 96: 000C0000
  bit 128: 00000000
  bit 160: 00000000
  bit 192: 00000000
  bit 224: 00000004
  bit 256: 0000007A
properties raw kernel attribute: 0
properties decoded bit map:
test_key: checking bit block 0 for any keys; found=0
test_key: checking bit block 32 for any keys; found=0
test_key: checking bit block 64 for any keys; found=0
test_key: checking bit block 96 for any keys; found=1
test_key: checking bit block 128 for any keys; found=1
test_key: checking bit block 160 for any keys; found=1
test_key: checking bit block 192 for any keys; found=1
test_key: checking bit block 224 for any keys; found=1
ID_INPUT_KEY=1
Unload module index
Unloaded link configuration context.

$ udevadm test-builtin input_id /devices/sound-9302.42/sound/card0/input4/
calling: test-builtin
=== trie on-disk ===
tool version: 219
file size: 6711498 bytes
header size 80 bytes
strings 1721914 bytes
nodes 4989504 bytes
Load module index
Network interface NamePolicy= disabled on kernel command line, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/usr/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/00-rmnet-kernel.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 21
capabilities/ev decoded bit map:
  bit 0: 00000021
capabilities/abs raw kernel attribute: 0
capabilities/abs decoded bit map:
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 0
capabilities/key decoded bit map:
properties raw kernel attribute: 0
properties decoded bit map:
test_key: no EV_KEY capability
Unload module index
Unloaded link configuration context.