Raspbmc: using a central mysql database

All my raspbmc's now share the same mysql db running on a tonido plugpc. That way all movie and music info is shared through all the raspbmc's. This post details the steps to setup this shared mysql for xbmc. First you have to setup the shared mysql db:

• Let mysql listen for incoming network connections (modify with the ip of your mysql device):
  edit /etc/mysql/my.cnf
#bind-address = 127.0.0.1
bind-address = 192.168.0.199
• restart mysql:
  /etc/init.d/mysql restart
• create the xbmc user:
  mysql -u root -p root_password

CREATE USER 'xbmc' IDENTIFIED BY 'xbmc';
GRANT ALL ON *.* TO 'xbmc';

Now, log on to your raspberry pi and create the $HOME/.xbmc/userdata/advancedsettings.xml file.
contents:
<advancedsettings>
    <videodatabase>
        <type>mysql</type>
        <host>192.168.0.199</host>
        <port>3306</port>
        <user>xbmc</user>
        <pass>xbmc</pass>
    </videodatabase>

    <musicdatabase>
        <type>mysql</type>
        <host>192.168.0.199</host>
        <port>3306</port>
        <user>xbmc</user>
        <pass>xbmc</pass>
    </musicdatabase>

  <pathsubstitution>
    <substitute>
      <from>special://profile/playlists/</from>
      <to>smb://tonidoplug2/your_share/xbmc/userdata/playlists/</to>
    </substitute>
    <!-- removed: this causes problems with the raspbmc plugin
    <substitute>
      <from>special://profile/addon_data/</from>
      <to>smb://tonidoplug2/your_share/xbmc/userdata/addon_data/</to>
    </substitute>-->
    <substitute>
      <from>special://profile/sources.xml</from>
      <to>smb://tonidoplug2/your_share/xbmc/userdata/sources.xml</to>
    </substitute>
    <substitute>
      <from>special://profile/mediasources.xml</from>
      <to>smb://tonidoplug2/your_share/xbmc/userdata/mediasources.xml</to>
    </substitute>
    <substitute>
      <from>special://profile/RssFeeds.xml</from>
      <to>smb://tonidoplug2/your_share/xbmc/userdata/RssFeeds.xml</to>
    </substitute>
    <substitute>
      <from>special://profile/favourites.xml</from>
      <to>smb://tonidoplug2/your_share/xbmc/userdata/favourites.xml</to>
    </substitute>
  </pathsubstitution>
</advancedsettings>
   
source: http://wiki.xbmc.org/index.php?title=HOW-TO:Sync_multiple_libraries/Setting_up_MySQL

Raspbmc: forcing HDMI connection on boot

My raspberry pi only boots succesfully from raspbmc when the TV attached to the HDMI connector is turned on. There is a simple workaround however:

• go to Programs / Raspbmc Settings / System Configuration.
• edit the "Additional config.txt settings" option with:
  hdmi_force_hotplug=1;hdmi_drive=2

Don't edit the /boot/config.txt file directly, as this change will be lost on the next raspbmc update.