Громкий звуковой сигнал от манджаро

Хорошо, после нескольких исследований я нашел выход. Во-первых, используйте udevadm monitorперед подключением и подключением. Вот результат:

KERNEL[126.555200] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2 (usb)
  KERNEL[126.555888] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0 (usb)
  KERNEL[126.556508] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.1 (usb)
  KERNEL[126.557829] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.2 (usb)
  KERNEL[126.558188] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.3 (usb)
  KERNEL[126.558548] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2 (usb)
  KERNEL[129.399848] add      /module/snd_seq_dummy (module)
  UDEV  [129.406959] add      /module/snd_seq_dummy (module)
  UDEV  [129.493966] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2 (usb)
  UDEV  [129.501782] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.2 (usb)
  UDEV  [129.505609] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.3 (usb)
  KERNEL[129.508606] add      /module/snd_rawmidi (module)
  UDEV  [129.510396] add      /module/snd_rawmidi (module)
  KERNEL[129.513459] add      /module/snd_usbmidi_lib (module)
  UDEV  [129.515605] add      /module/snd_usbmidi_lib (module)
  KERNEL[129.516631] add      /module/snd_hwdep (module)
  UDEV  [129.518617] add      /module/snd_hwdep (module)
  KERNEL[129.535977] add      /module/snd_usb_audio (module)
  UDEV  [129.537881] add      /module/snd_usb_audio (module)
  KERNEL[129.538452] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.1 (usb)
  KERNEL[129.538547] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1 (sound)
  KERNEL[129.539135] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/midiC1D0 (sound)
  KERNEL[129.539260] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/seq-midi-1-0 (snd_seq)
  KERNEL[129.539985] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/controlC1 (sound)
  KERNEL[129.541172] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0 (usb)
  UDEV  [129.541345] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.1 (usb)
  KERNEL[129.541428] add      /bus/usb/drivers/snd-usb-audio (drivers)
  UDEV  [129.542776] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0 (usb)
  UDEV  [129.542917] add      /bus/usb/drivers/snd-usb-audio (drivers)
  KERNEL[129.549489] add      /module/snd_seq_midi_event (module)
  UDEV  [129.551648] add      /module/snd_seq_midi_event (module)
  KERNEL[129.552118] add      /module/snd_seq_midi (module)
  KERNEL[129.552213] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/seq-midi-1-0 (snd_seq)
  KERNEL[129.552288] add      /bus/snd_seq/drivers/snd_seq_midi (drivers)
  UDEV  [129.554430] add      /module/snd_seq_midi (module)
  UDEV  [129.554572] add      /bus/snd_seq/drivers/snd_seq_midi (drivers)
  UDEV  [129.561871] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2 (usb)
  UDEV  [129.564936] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.1 (usb)
  UDEV  [129.566125] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1 (sound)
  UDEV  [129.568261] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/seq-midi-1-0 (snd_seq)
  UDEV  [129.570243] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/midiC1D0 (sound)
  KERNEL[129.573057] change   /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1 (sound)
  UDEV  [129.607147] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/controlC1 (sound)
  UDEV  [129.609881] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0 (usb)
  UDEV  [129.611644] bind     /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/seq-midi-1-0 (snd_seq)
  UDEV  [129.618931] change   /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1 (sound)

Заметив последнюю строку UDEV [129.611644] bind /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/seq-midi-1-0 (snd_seq), я подключил MIDI-клавиатуру USB и сделал:

devadm info -a /sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2\:1.0/sound/card1/seq-midi-1-0/> /tmp/udev`

Среди выходов есть в первых строках:

  looking at device '/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1/seq-midi-1-0':
    KERNEL=="seq-midi-1-0"
    SUBSYSTEM=="snd_seq"
    DRIVER=="snd_seq_midi"

  looking at parent device '/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0/sound/card1':
    KERNELS=="card1"
    SUBSYSTEMS=="sound"
    DRIVERS==""
    ATTRS{number}=="1"
    ATTRS{id}=="Impulse"

  looking at parent device '/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/1-1.2:1.0':
    KERNELS=="1-1.2:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="snd-usb-audio"
    ATTRS{bInterfaceProtocol}=="00"
    ATTRS{bInterfaceSubClass}=="01"
    ATTRS{interface}=="Novation Impulse"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{supports_autosuspend}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{authorized}=="1"
    ATTRS{bNumEndpoints}=="00"
    ATTRS{bInterfaceClass}=="01"

Интересная информация: SUBSYSTEMи DRIVERS. Поэтому я изменил правило udev на:

ACTION=="bind", SUBSYSTEM=="snd_seq", DRIVERS=="snd-usb-audio", RUN+="/bin/su -c /home/pi/piano_connect - pi"
ACTION=="remove", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="1235", ATTRS{idProduct}=="001a", RUN+="/usr/bin/aconnect -x"

Здесь я изменил ДЕЙСТВИЕ на «привязать» из-за первой команды(udevadm monitor)и сопоставил с SUBSYSTEMи DRIVERSвместо идентификаторов продукта. И это работает как шарм! Надеюсь, это помогло.:)