[mythtvnz] upgrade from V 31 to V 32

[Stephen Worthington]

On Sun, 13 Mar 2022 11:10:15 +1300, you wrote:

>I successfully updated to v32 following Stephen's instructions but I 
>cannot run mythtv-setup via a VNC session to my headless backend.
>
>I will have to wait until I am fit and mobile enough (after an operation 
>on my ankle) to connect it to a screen and keyboard.
>
>Rob

To get VNC to work on a headless machine, you need to configure it
with the dummy video driver.  I have been playing with this on my
"lith" PC (Ubuntu 20.04) and have got it to work.  You install the
xserver-xorg-video-dummy package, and use an /etc/X11/xorg.conf file
that looks something like this:

Section "ServerLayout"
   Identifier   "DefaultLayout"
   Screen       "Screen1"
EndSection

Section "ServerFlags"
   Option       "DefaultServerLayout"   "DefaultLayout"
EndSection

Section "Monitor"
  Identifier "Dummy1"
  HorizSync 28.0-80.0
  VertRefresh 48.0-75.0
  # https://arachnoid.com/modelines/
  # 1920x1080 @ 60.00 Hz (GTF) hsync: 67.08 kHz; pclk: 172.80 MHz
  Modeline "1920x1080_60.00" 172.80 1920 2040 2248 2576 1080 1081 1084
1118 -HSync +Vsync
  # 1920x1080 @ 50.00 Hz (GTF) hsync: 55.60 kHz; pclk: 141.45 MHz
  #Modeline "1920x1080_50.00" 141.45 1920 2032 2232 2544 1080 1081
1084 1112 -HSync +Vsync
EndSection

Section "Device"
  Identifier "Device1"
  Driver "dummy"
  VideoRam 256000
EndSection

Section "Screen"
  DefaultDepth 24
  Identifier "Screen1"
  Device "Device1"
  Monitor "Dummy1"
  SubSection "Display"
    Depth 24
    Modes "1920x1080_60.00"
  EndSubSection
EndSection

My email client wraps long lines - the Modeline lines are all on one
line.

You can use the modeline calculator on the URL above to set up a
screen definition that matches your actual monitor if you want that
rather than 1920x1080.  My monitor is 1920x1200.

I think it will work also if you set up a "Screen0" definition that
works with your real monitor when that is plugged in, and set
"Screen0" ahead of "Screen1" in the "Serverlayout" section.  Then it
should connect to the real monitor if it is present, and will create
the dummy monitor as a second screen.  If you do that, when the real
monitor is connected, it will be DISPLAY=:0.0 and the dummy monitor
will be DISPLAY=:0.1.  From 

In any case, you can keep two xorg.conf.xxx files and just copy the
one you want for the next boot to be xorg.conf via ssh.  These are the
xorg.conf sections I use for my real screen, using my Nvidia GT1030
card:

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "DELL 2707WFP"
    HorizSync       30.0 - 81.0
    VertRefresh     56.0 - 76.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "NVIDIA GeForce GT 1030"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DFP-1"
    Option         "metamodes" "nvidia-auto-select +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Via SSH, you can see what your screens are using xrandr.  I have
several PCs on an HDMI KVM switch, and when the switch is set to a PC
other than lith, lith's video card sees no monitor connected and VNC
will not work on the main screen, but if I start a second VNC server
on the dummy screen, that works.  This is what xrandr shows in that
situation:

stephen at lith:~$ DISPLAY=:0.0 xrandr
Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 32767 x 32767
DVI-D-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected primary (normal left inverted right x axis y axis)
stephen at lith:~$ DISPLAY=:0.1 xrandr
xrandr: Failed to get size of gamma for output default
Screen 1: minimum 320 x 240, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
   1920x1080     60.00*
   1680x1050     70.00    60.00
   1400x1050     70.00    60.00
   1600x900      60.00
   1280x1024     75.00    60.00
   1440x900      60.00
   1400x900      60.00
   1280x960      60.00
   1368x768      60.00
   1360x768      60.00
   1280x800      60.00
   1152x864      75.00    70.00    60.00
   1280x720      60.00
   1024x768      75.00    70.00    60.00
   1024x576      60.00
   960x600       60.00
   832x624       75.00
   960x540       60.00
   800x600       75.00    72.00    60.00    56.00
   840x525       70.00    60.00
   864x486       60.00
   700x525       70.00    60.00
   800x450       60.00
   640x512       75.00    60.00
   720x450       60.00
   700x450       60.00
   640x480       75.00    73.00    60.00
   684x384       60.00
   680x384       60.00
   640x400       60.00
   576x432       75.00    70.00    60.00
   640x360       60.00
   512x384       75.00    70.00    60.00
   512x288       60.00
   416x312       75.00
   480x270       60.00
   400x300       75.00    72.00    60.00    56.00
   432x243       60.00
   320x240       75.00    73.00    60.00

To start a second copy of the x11vnc server via ssh, I do this command
as root:

/usr/bin/x11vnc -auth guess -forever -loop -noxdamage -repeat -rfbauth
/etc/x11vnc.pass -rfbport 5901 -shared -noxrecord -display :0.1 &

(all one line)

The second VNC server will run on port 5901 instead of the default
5900 which is in use by the first x11vnc server on the :0.0 display
that is started automatically at boot time.