Xfce no panel

It doesn't happen often (but I'd love to know why), but I lost by Xfce panel again today. Luckily this is easy to fix. Open a terminal (right mouse click) and re-start the panel with:

xfce4-panel &

Now that you have you're panel working make this permanent by removing current session information:

rm -rf ~/.cache/sessions/

Logout and restart your session.
One final hint, backup your Xfce4 settings! I alias the backup command and keep a local and remote copy of the generated archive:

alias backupxfce='cd ~;tar jcvf Backups/xfce4.tar.bz2 .config/xfce4'

This alias will create a bzip2 archive.

XBMC on a ACER Aspire Revo R3700

The following guide is to assist installation of XBMC onto an ACER Aspire Revo R3700 320G/ 2G RAM Mini PC running Ubuntu 10.04. See also my notes on installing MCE remote for XBMC.

Please feel free to suggest corrections or clarifications.

Installation of Ubuntu 10.04
I installed Ubuntu 10.04 from USB. Instructions for this can be found at Ubuntu here.

References

https://help.ubuntu.com/community/Installation/FromUSBStick
http://forum.xbmc.org/showthread.php?t=53812
http://wiki.xbmc.org/index.php?title=Installing_XBMC_for_Linux

Enable SSH

Enable ssh for easy remote management.

• enable X11 forwarding, in /etc/ssh/sshd_config set,
  X11Forwarding yes
  
• enable SSH daemon with,
  update-rc.d
ssh defaults
• restart SSH daemon with,
  service ssh restart
• on the server allow an X client with,
  xhost +[ip_of_client]

To start a session with X enabled,

ssh -X user@192.168.0.6

To copy a file from local to remote host use,

scp local_file user user@192.168.0.6:/home/user/

References

http://www.cyberciti.biz/faq/howto-runlevel-configuration-tool-to-start-service/
http://www.go2linux.org/linux/2011/02/my-top-five-ssh-tips-and-tricks-small-cheatsheet-914

Replace GDM On Startup

I’ll assume that the user name for access to you XMBC box is xmbc.

• Auto-login xmbc user, edit /etc/init/tty2.conf
exec /bin/su xmbc -l -c "/bin/bash --login -c /usr/bin/startx > ~xmbc/.tty2.errors 2>&1"
  Where errors are reported into ~xmbc/.tty2.errors
  
• Put xmbc startup in users X initialisation, edit ~xmbc/.xinitrc
exec /usr/bin/ck-launch-session /usr/bin/dbus-launch --exit-with-session /usr/bin/xbmc --standalone -fs > .xinitrc.errors 2>&1
  Where errors are reported into ~xmbc/.xinitrc.errors
  
• Ensure user has correct authorities. The following fixes the error,
  X: user not authorized to run the X server, aborting.
  Edit /etc/X11/Xwrapper.config and replace allowed_users=console with
allowed_users=anybody
  
• Remove GDM from startup.
  mv /etc/init/gdm.conf /etc/init/gdm.conf.bak
update-rc.d -f gdm remove
  
• Reboot.
  

To recover GDM reverse the fourth step. GDM will then start despite errors being logged by xbmc complaining that startx is already active.

References

http://ubuntuforums.org/showthread.php?t=625230

Sound over HDMI

This was by far the trickiest to set up on the Acer. I've used alsa in preference to pulse. I also un-installed pulse just to be sure it wouldn't clash with my alsa settings.

• For this XBMC installation I've used the custom audio output of plughw:1,7
  
• In /etc/asound.conf I added,
  # source: https://bbs.archlinux.org/viewtopic.php?id=100759
  pcm.dmixer {
       type dmix
       ipc_key 2048
       slave {
           pcm "hw:1,7"        # always use pure hw. dmix will resample
           period_size 512     # a reasonable default
           buffer_size 4096
           rate 48000          # HDMI assumes 48kHz
           format S16_LE       # a  reasonable default
       }
       bindings {
           0 0
           1 1
       }
   }
   pcm.!default {
       type plug
       slave.pcm  "dmix:1,7"
   }

• Open alsamixer and ensure channels are not muted. Muted are keyed as (MM), non-muted are something like, (00).
• Save the volumes of alsamixer with,
  alsactl store 0
• To test, aplay -D plughw:1,7 /usr/share/sounds/alsa/Front_Center.wav

References

https://bbs.archlinux.org/viewtopic.php?id=100759
http://guide.ubuntuforums.org/showthread.php?t=1625530&page=2
http://ubuntuforums.org/showthread.php?t=1532355
http://forums.boxee.tv/showthread.php?t=21106

Wireless drops connection periodically

The Revo wireless card raLink rt3090 is known to cause some problems.

• First check with setup with,
  lshw -C network
This will show a wealth of wireless information.
  
• To see what drivers are actually loaded try,
  lsmod | grep -e rt2 -e rt3
  For this device we only want to see rt3090 and not any of the rt2* drivers.
  
• To exclude the rt2* drivers append to /etc/modprobe.d/blacklist.conf the following,
  # cat /etc/modprobe.d/blacklist.conf
blacklist ndiswrapper
blacklist rt2800pci
blacklist rt2860sta
blacklist acer-wmi
• <note – the last line must be blank>
  
• Next ensure wireless driver is loaded in /etc/modules
# wireless drivers for Ralink 2860
rt3090sta

• To get interface information, use on or all of,
  nm-tool
lshw -C network
iwlist scan
  
• To check clients to your local network,
  nmap -sP 192.168.0.0/29
  
• To restart wireless,
  service network-manger restart
  

References

http://crunchbanglinux.org/wiki/howto/rt2860sta_wireless