Bluetooth earbud play-pause fix

Bluetooth earbud play/pause fix (Bose QC Ultra II)

Ubuntu (GNOME, X11, PipeWire + BlueZ). Tapping the earbud to play/pause didn't work, while next/prev did. Refined symptom: pause works, resume (play) never does. Works fine on phone/other OSes.

1   Root cause

On every tap the earbuds emit AVRCP PAUSE — they never send PLAY. They decide PLAY vs PAUSE from the playback status the source reports back to them; this PC never reports "paused," so the earbuds assume "playing" forever and always send PAUSE. Phone reports state correctly, so the toggle works there.

Confirmed at the key level: the AVRCP input device "Escape Pods (AVRCP)" emits KEY_PAUSECD (code 201) on every tap, never KEY_PLAYPAUSE. gsd-media-keys turns that into an MPRIS Pause call — so pause works, resume can't.

2   Fix

Remap that one key (KEY_PAUSECD → KEY_PLAYPAUSE), scoped to only the earbud device, using xremap. gsd then issues a proper PlayPause toggle against the player's real state, which the desktop knows correctly.

(Note: mpris-proxy — /usr/lib/bluetooth/mpris-proxy as a user service — was an earlier partial fix and is still installed; it gets "pause" working but not resume. The xremap remap below is what actually fixes resume.)

2.1   Install xremap

#  1. Download the prebuilt X11 binary (check for newer release)
cd /tmp
curl -fsSL -o xremap-x11.zip \
  https://github.com/xremap/xremap/releases/latest/download/xremap-linux-x86_64-x11.zip
unzip -o xremap-x11.zip
chmod +x xremap

#  2. Config: /etc/xremap/config.yml
sudo mkdir -p /etc/xremap
sudo tee /etc/xremap/config.yml >/dev/null <<'EOF'
modmap:
  - name: earbuds-playpause
    device:
      only: ["Escape Pods (AVRCP)"]
    remap:
      KEY_PAUSECD: KEY_PLAYPAUSE
EOF

#  3. Install binary + root systemd service
sudo install -m755 /tmp/xremap /usr/local/bin/xremap
sudo tee /etc/systemd/system/xremap.service >/dev/null <<'EOF'
[Unit]
Description=xremap - remap Bose earbud play/pause key to a real toggle
After=bluetooth.target

[Service]
Type=simple
# --device scopes the grab to ONLY the earbuds (leaves the keyboard alone).
# --watch=device re-grabs automatically when the earbuds reconnect.
ExecStart=/usr/local/bin/xremap --watch=device --device "Escape Pods (AVRCP)" /etc/xremap/config.yml
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

sudo systemctl daemon-reload
sudo systemctl enable --now xremap.service
sudo systemctl status xremap.service --no-pager

Then play something in Spotify and tap the earbud — it should toggle.

1   Notes / gotchas

• Must run privileged: /dev/input/event* is root:input and xremap also needs /dev/uinput. Running as a root system service is simplest.
• Always pass --device "Escape Pods (AVRCP)" — without it xremap grabs all keyboards (it grabbed the Keychron in testing).
• If the earbud device name ever changes, update it in both the service --device flag and the config device.only.

2   How the diagnosis was done (reusable)

Find the AVRCP input device:

grep -iA5 "AVRCP" /proc/bus/input/devices   # -> Name + event number

See what key a tap actually emits (no extra packages needed; needs sudo because the device is root:input). Save as /tmp/readkey.py:

#!/usr/bin/env python3
import struct, select, time
FMT="llHHi"; SZ=struct.calcsize(FMT)
NAMES={119:"KEY_PAUSE",163:"KEY_NEXTSONG",164:"KEY_PLAYPAUSE",165:"KEY_PREVIOUSSONG",
       201:"KEY_PAUSECD",200:"KEY_PLAYCD",207:"KEY_PLAY"}
dev="/dev/input/event25"   # adjust to the AVRCP event number
with open(dev,"rb") as f:
    end=time.time()+8
    while time.time()<end:
        r,_,_=select.select([f],[],[],0.5)
        if not r: continue
        t,c,v=struct.unpack(FMT,f.read(SZ))[2:]
        if t==4 and c==4: print(f"  scancode: 0x{v&0xffffffff:x}")
        if t==1 and v==1: print(f"  pressed: code={c} {NAMES.get(c,'???')}")

Run sudo python3 /tmp/readkey.py and tap. (No MSC_SCAN scancode line means a native udev hwdb remap won't work — hence xremap.)

See what reaches MPRIS while tapping:

dbus-monitor --session "interface='org.mpris.MediaPlayer2.Player'"