Difference between revisions of "User:Lwoggardner"

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(Suspend to RAM on idle)
Line 125: Line 125:
   logger -s -t "mythtv-checkidle"
   logger -s -t "mythtv-checkidle"
# The frontend is still running
# Regardless of WOL settings and going into standbymode the 0.25 front-end
# simply cannot cope with the backend dropping out unexpectedly so we
# keep the BE up until the FE suspends itself
check_frontend mythion && {
check_frontend mythion && {
     echo "Frontend is still up" | log
     echo "Frontend is still up" | log

Revision as of 00:38, 2 February 2013

I was keeping track of where I was at with Myth on my home wiki, but then figured I might as well share it here!

My Setup

MythBuntu 12.04 with separated front-end/backend

  • Live TV/TV recording Free to air HD/SD (from Sydney, Australia)
  • Multi-rec
  • DTS/AC3 passthrough including 5,1 surround digital out
  • MythMusic
  • MythGallery
  • MythVideo
  • Frontend Suspend to RAM + Wake On USB
  • Backend Suspend to RAM



  • HDDs totalling 1.2Tb
  • Intel S775 Core 2 Q6600 Quad-Core CPU
  • Gigabyte S775 GA-G33M-S2 Motherboard
  • 4GB RAM
  • PCI Hauppauge Nova-T-500 MCE(OEM) Dual DVBT tuner
  • PCI Hauppauge Nova-TD 400 Dual DVBT tuner



  • Channel 9, Gem, GO will not tune. The dtv_multiplex.network_id is null - set to 4114 seems to fix things.

Shepherd grabber

Standard install except cron job is disabled and allow mythtv to run mythfilldatabase. This is to allow mythtv to also be in control of suspend.

Suspend to RAM on idle

Why Suspend to RAM and not just a full shutdown that would "just work"? Partly due to boot speed and partly just because.


  • mythbackend controls idle detection, supported by a custom script to check other reasons to stay up, and sudo rules to allow passwordless root activity
  • suspend needs to unload dvb/usb modules which requires stopping mythbackend which means triggering suspend via upstart
  • wake up for recordings triggered by /sys/class/rtc as per ACPI_Wakeup, hwlock-save update disabled via upstart override
  • wake up for daily processing (anacron) triggered by cron running on my (always on) DD-WRT enabled router issuing a WOL
  • wake up for serving adhoc web requests (mythweb et al) triggered by [custom router script]

Settings (set via mythweb as server is basically headless)

Name Setting Value Why
Pre ShutdownWakeUp Check Command preSDWUCheckCommand /home/mythtv/bin/check-idle.sh check if i'm logged in, or machine is in use for some other reason
Block ShutdownWakeUp without client blockSDWUwithoutClient 0 because this is a backend only machine
Set Wakeup time command SetWakeuptimeCommand sudo /usr/local/sbin/set-wakeup.sh $time
Server Halt command ServerHaltCommand sudo /usr/local/sbin/emit-suspend.sh can't suspend directly because we need to shutdown mythbackend during suspend
Wakeup time format WakeupTimeFormat time_t as per ACPI wakeup page to use /sys/class/rtc

LOG_AGE="5 minutes ago"

check_frontend() {
# Not this doesn't care about what the FE is doing, just that it is up
expect - $1 <<'END_EXPECT'
#exp_internal 1
set timeout 2
log_user 0
set prompt "# "
set cmd "query location\r"
set frontend [lindex $argv 0]
spawn netcat $frontend 6546
  expect {
        timeout { send_user "\nNo prompt\n"; exit 1 }
        eof { send_user "\nNo output\n"; exit 1 }

  send $cmd
  expect  {
       timeout { send_user "\nNo response\n"; exit 1 } 
       eof { send_user "\nPremature EOF\n"; exit 1 }
       -re "query location\r\n(.*)\r\r\n# "
  set location $expect_out(1,string)
  send "exit\r"
  expect eof
  send_user "MythTVLocation:$location\n"


log() {
  logger -s -t "mythtv-checkidle"

# Regardless of WOL settings and going into standbymode the 0.25 front-end
# simply cannot cope with the backend dropping out unexpectedly so we
# keep the BE up until the FE suspends itself
check_frontend mythion && {
    echo "Frontend is still up" | log
    exit 1

# anacron is running daily, weekly or monthly jobs
pgrep 'anacron' && {
    echo "Anacron job is running" | log
    exit 1

# apache request in last 5 minutes
if [ -f $ACCESS_LOG -a `stat -c %Y $ACCESS_LOG` -gt `date --date "$LOG_AGE" "+%s"` ] ; then
    echo "Web server in use" | log
    exit 1

# users are logged in
if [ `who | wc -l` -gt 0 ] ; then
    echo "Users logged in" | log
    who | log
    exit 1

/usr/bin/mythshutdown -v --check | log

exit ${PIPESTATUS[0]}
#Enable mythtv to set the real time clock and emit the suspending event without a password prompt

%mythtv ALL = NOPASSWD: /usr/local/sbin/emit-suspend.sh, /usr/local/sbin/set-wakeup.sh
#$1 is the first argument to the script. It is the time in seconds since 1970
#this is defined in mythtv-setup with the time_t argument

echo 0 > /sys/class/rtc/rtc0/wakealarm      #this clears your alarm.
echo $1 > /sys/class/rtc/rtc0/wakealarm     #this writes your alarm
# Suspend via upstart
initctl emit suspending
start on (suspending)

   logger -t "suspending" "Suspending via upstart" 
end script
# The dvb modules need to be unloaded to allow suspend/resume to work
# To unload the modules mythbackend needs to be stopped
# NOTE: Suspend cannot be executed in a child process of mythbackend itself (eg via server halt command)
# since it will simply abort at the point we stop mythbackend below. If this is required use upstart or some
# other means to decouple pm-suspend from the mythbackend process.


echo "Will now $1 mythtv" | tee -a $LOG

case $1 in
        stop mythtv-backend 2>&1 | tee -a $LOG
        while [ `lsmod | grep "^${MODULE}" | wc -l` -gt 0 ]
            sleep 1
            modprobe -r $MODULE 2>&1 | tee -a $LOG 
        modprobe $MODULE
        start mythtv-backend | tee -a $LOG



  • ZOTAC ionitx-d-e board, 2G memory
  • Szrealan E-2011 case (tiny!)
  • External DVD player
  • 1Tb external e-Sata drive
  • BenQ PE8700 DLP Projector
  • Sony Bravia TV over HDMI
  • CambridgeAudio AV receiver


  • MythBuntu 12.04 64bit
  • Synergy to allow laptop to be the keyboard/mouse.


Enable Wake on USB

We need to enable USB0 in /proc/acpi/wakeup

Note if USB2 is also enabled, then the board immediately wakes up regardless, unsure if this is due to another USB device

Seems to be enabled by default for Mythbuntu 12.04 but Current cheap as Chinese remote does not send the wakeup signal from the power button unfortunately

Auto-start X

  • disabled lightdm in via upstart override (echo 'manual' > /etc/init/lightdm.override)
  • Simple mingetty startup with a tty definition and a startx script in the console
  • user .xsession linked to /usr/share/mythbuntu/session.sh so we get the same xfce startup.
# tty7 - mythtv
start on runlevel [23]
stop on runlevel [!23]

exec /sbin/mingetty --autologin=mythtv tty7

Appended to detect if we are on tty7, in which case we start-up X with an optional layout specified in ~/.mythrc

Note that when X is stopped we automatically logout and respawn

start-frontend() {
if [ -r $MYTHRC ] ; then
   . $MYTHRC

[ ! -z "$LAYOUT" ] && LAYOUT_SPEC="-layout $LAYOUT"

startx --  $LAYOUT_SPEC -logverbose 5

tty | grep tty7 && start-frontend

For PE8700 Samsung LCD. See also the tips for the NVidiaProprietaryDriver

The FX5200 cards were the cause of my DVI problems on my projector. Apparently they freak out a PCB component causing the EDID data to become corrupt. (a Gigabyte card lasted from Aug 2006 to Dec 2007. Fortunately the new nvidia driver allow you to use a CustomEDID to load the data from a file.

Option ExactModeTimingsDVI is also important for the projector.

Option "UseEDIDDpi" "false" or some equivalent control of DPI is important for the Samsung television otherwise you get really small fonts (fixed in 0.21)

There are two layouts, the default uses outputs via VGA to a Samsung LCD television, the second uses DVI to the PE8700 projector.

Section "ServerLayout"
    Identifier     "Main" # Output to Samsung LCD television
    Screen         0 "LCD[1]" 0 0
    Option         "Xinerama" "off"

Section "ServerLayout"
    Identifier     "Projector"
    Screen         0 "Projector[0]" 0 0
    Option         "Xinerama" "off"
Section "Module"
        Load    "glx"

Section "Device"
    Identifier     "ION-GPU[0]"
    Driver         "nvidia"
    BusID          "PCI:3:0:0"
    Screen         0
    #This prevents the cursor being displayed on resume from suspend
    Option         "HWCursor" "off"

Section "Screen"
    Identifier     "LCD[1]"
    Device         "ION-GPU[0]"
    Monitor        "AnyMonitor"
    DefaultDepth    24
    Option         "UseDisplayDevice" "DFP-1" # HDMI
    Option         "ConnectedMonitor" "DFP-1"

Section "Screen"
    Identifier     "LCD[0]"
    Device         "ION-GPU[0]"
    Monitor        "AnyMonitor"
    DefaultDepth    24
    Option         "ConnectedMonitor" "CRT-1"
    Option         "UseEDIDDpi" "FALSE" #Computed DPI values not so good for TV display
    Option         "UseDisplayDevice" "CRT-1" # VGA out
    SubSection     "Display"
        Depth       24
        Modes       "1360x768" "800x600"

Section "Screen"
    Identifier     "Projector[0]"
    Device         "ION-GPU[0]"
    Monitor        "AnyMonitor"
    Option         "ConnectedMonitor" "DFP"
    Option         "UseDisplayDevice" "DFP" # DVI out
    Option         "CustomEDID" "DFP-0:/etc/X11/benq-c.bin"

    DefaultDepth    24
    SubSection     "Display"
        Depth       24
        Modes       "1280x720" "800x600"

Section "Monitor"
    Identifier   "AnyMonitor"
    Option       "DPMS"
    Option       "ExactModeTimingsDVI" "true"
    Option       "RenderAccel" "true"


Start a ruby program that listens to /dev/lircd and manages -

  • mythtv via updating the database + network control port
  • the AV receiver via RS232 - volume/mute, power on/off, input type
  • alsa via calls to amixer - volume/mute, digital/analog outputs
  • suspend on lirc idle or power button
  • restart specifying TV or Projector layout

#store our dbus session and display where our kill script can pick it up
export | egrep "DBUS_SESSION_BUS_ADDRESS|DISPLAY" > ~/.xsession-export

#Run unclutter to hide the cursor after resume - not required - see HWCursor in xorg.conf
#unclutter -display $DISPLAY &

#run our main lirc control program
/home/mythtv/bin/audiomodeswitch/main.rb &

# We use dbus-send because it seems to block until resume which is what we want
echo "Suspending"

dbus-send --system --print-reply --dest=org.freedesktop.Hal /org/freedesktop/Hal/devices/computer \
        org.freedesktop.Hal.Device.SystemPowerManagement.Suspend int32:2

echo "Resumed"

Script is called by the ruby program, but also useful to restart from ssh


[ -f $HOME/.xsession-export ] && . $HOME/.xsession-export
echo "killing mythfrontend"
pkill mythfrontend
#pkill unclutter
echo "xfce logout $DISPLAY"
xfce4-session-logout --logout --fast

LIRC Remote Control

Standard mythbuntu setup for MCE remote.


Onboard sound


Could probably do better 48/44kHz switching on the analog output between music and video but if that is important we just go digital passthrough and let the receiver do the work.

In myth config, you can see that default sound device is ALSA:myth-video, the passthrough device is ALSA:myth-passthru, and mythmusic uses ALSA:myth-music. the AC3PassThru and DTSPassThru settings are managed by the ruby program

#First line comment

pcm.myth-music {
  type copy
  slave.pcm "default"

ctl.myth-music {
  type hw
  card 0

pcm.myth-video {
  type copy 
  slave.pcm "default"

ctl.myth-video {
  type hw
  card 0

pcm.myth-passthru {
  type copy
  slave.pcm = "spdif"

ctl.myth-passthru {
  type hw
  card 0


TODO - Works nicely through the WRT310N router etc, but we have a hard drive have decided to stick with Mythbuntu for now.


Mythbuntu 12.04

Reconfigured from scratch for no particular reason

Mythbuntu 10.10

100% clean on server

front end was missing non-versioned symlink for vdpau nvidia library

ln -s /etc/alternatives/libvdpau_nvidia.so /usr/lib/libvdpau_nvidia.so

Mythbuntu 9.10

100% clean on server

front end needed /etc/events.d/tty7 moved to /etc/init/tty7.conf

Mythbuntu 8.10


upgrade smooth