---
layout: post
title: "Get a Bluetooth keyboard work with Arch Linux"
date: 2016-07-07 14:49:18 +0200
categories: linux
---

<p>
  I've recently got a Rapoo E6100. This is a minimal and space saving Bluetooth
  3.0 keyboard. If you pair it with Windows 10, it will remain paired after
  reboot, giving the possibility to use it since the login screen. After
  installing the Bluetooth stack on my Arch via the <code>bluez</code> and
  <code>bluez-utils</code> packages I thought the pairing process would be as
  simple as Windows if I used the KDE GUI menus for Bluetooth management. That's
  not true. The keyboard, once paired, will reconnect automatically just after
  <code>plasmashell</code> loaded, leaving me without keyboard during the SDDM
  login screen and, of course, during a non-graphical session.
</p>

<p>
  As usual, i've searched help in the ArchWiki, founding
  <a href="https://wiki.archlinux.org/index.php/Bluetooth_keyboard">this</a>
  article. With that, i've succesfully reconnected my Bluetooth keyboard using
  the <code>bluetoothctl</code> utility. The next step was configuring the
  service for auto connection during boot. I've created the
  <code>btkbd.conf</code> and the <code>btkbd.service</code> files, enabling the
  last one with systemd. Let's give a look to the service file:
</p>

<p>
  {% highlight bash linenos %} [Unit] Description=systemd Unit to automatically
  start a Bluetooth keyboard
  Documentation=https://wiki.archlinux.org/index.php/Bluetooth_Keyboard
  Requires=dbus-org.bluez.service After=dbus-org.bluez.service
  ConditionPathExists=/etc/btkbd.conf ConditionPathExists=/usr/bin/hcitool
  ConditionPathExists=/usr/bin/hciconfig [Service] Type=oneshot
  EnvironmentFile=/etc/btkbd.conf ExecStart=/usr/bin/hciconfig ${HCIDEVICE} up #
  ignore errors on connect, spurious problems with bt? # so start next command
  with - ExecStart=-/usr/bin/hcitool cc ${BTKBDMAC} [Install]
  WantedBy=multi-user.target {% endhighlight %}
</p>

<p>
  Line 13 enables the Bluetooth dongle, and line 16 connects it to the keyboard
  we gave the mac address in <code>/etc/btkbd.conf</code>. This should work
  flawlessly, right? Of course it doesn't. The service starts before the
  <code>dbus-org.bluez.service</code> is loaded and fails. However, if the
  service is started manually after login the Bluetooth keyboard works. After
  hours of trying figuring out what was wrong I've almost asked for a return on
  Amazon! The last attempt I made was with sddm disabled and involved built from
  scratch service:
</p>

<p>
  {% highlight bash linenos %} [Unit] Description=systemd Unit to automatically
  start a Bluetooth keyboard [Service] Type=oneshot ExecStart=/bin/hciconfig
  hci0 up ExecStart=/bin/hcitool cc 00:11:22:33:44:55 [Install]
  WantedBy=bluetooth.target {% endhighlight %}
</p>

<p>
  This incredibly worked. I think the problem was that
  <code>multi-user.target</code> that needs to be reached earlier than
  <code>bluetooth.target</code>. I got rid of all the tidiness of the ArchWiki
  solution just to be sure that was not the problem, but I think you can use all
  of that just correcting <code>WantedBy=</code>. Currently I haven't an
  ArchWiki account nor a forum one, but as soon as I'll register I'll correct
  the article.
</p>

<p>
  Last thing: I discovered that my Bluetooth dongle is CSR 8510 A10 based so
  expect some ramblings about
  <a
    href="http://www.0xf8.org/2014/02/the-crux-of-finding-a-hid-proxy-capable-usb-bluetooth-adapter/"
    >hid proxy</a
  >.
</p>