Misleading VNC Server error – fontPath

Feb 21, 2012 • alan


I am working from home today, which involves a combination of working locally on my laptop, but also remotely accessing some resources at the office. My current tool of choice for accessing the PC on my desk is VNC.

A note for Windows users — a VNC server on Windows will share the desktop session that is on your monitor. The default VNC server on Linux does not do this. Instead, it creates a brand new session that is completely independent of what’s on the monitor. If a Linux user wants the same experience that Windows users are used to, he can run “x11vnc”, a VNC server that copies the contents of whatever’s on the monitor and shares that with the remote user.

So when I access my PC remotely, I shell in to my desktop PC and I start a VNC server. I can specify the virtual screen size and depth, which is useful if I want to make it large enough to fill most of my laptop screen, but still leave a margin for stuff like window decorations. The command I use looks like this:

vncserver :1 -depth 32 -geometry 1600x1000 -dpi 96

This morning, when I started my VNC session, it responded with some errors about my fonts. Huh?

Couldn't start Xtightvnc; trying default font path.
Please set correct fontPath in the vncserver script.
Couldn't start Xtightvnc process.

21/02/12 10:40:55 Xvnc version TightVNC-1.3.9
21/02/12 10:40:55 Copyright (C) 2000-2007 TightVNC Group
21/02/12 10:40:55 Copyright (C) 1999 AT&T Laboratories Cambridge
21/02/12 10:40:55 All Rights Reserved.
21/02/12 10:40:55 See http://www.tightvnc.com/ for information on TightVNC
21/02/12 10:40:55 Desktop name 'X' (chutney:2)
21/02/12 10:40:55 Protocol versions supported: 3.3, 3.7, 3.8, 3.7t, 3.8t
21/02/12 10:40:55 Listening for VNC connections on TCP port 5902

Fatal server error:
Couldn't add screen
21/02/12 10:40:56 Xvnc version TightVNC-1.3.9
21/02/12 10:40:56 Copyright (C) 2000-2007 TightVNC Group
21/02/12 10:40:56 Copyright (C) 1999 AT&T Laboratories Cambridge
21/02/12 10:40:56 All Rights Reserved.
21/02/12 10:40:56 See http://www.tightvnc.com/ for information on TightVNC
21/02/12 10:40:56 Desktop name 'X' (chutney:2)
21/02/12 10:40:56 Protocol versions supported: 3.3, 3.7, 3.8, 3.7t, 3.8t
21/02/12 10:40:56 Listening for VNC connections on TCP port 5902

Fatal server error:
Couldn't add screen

I scratched around for a while, looking at font settings. Then I tried some experiments. I changed the dimensions from 1600×1000 to 800×600. Suddenly it worked.

Then I noticed that the VNC startup script makes some assumptions. If the VNC server can not start, it assumes that the problem is with the fonts, and it tries again using the default font path. In my case, the VNC server failed because I had specified a large screen (1600x1000x32) and there was already another session on the physical monitor. VNC could not start because it had run out of video memory.

So my solution? I had a choice. I could reduce the size or depth of the virtual screen, or I could kill the existing session that was running on my desktop.

Don’t believe everything you read. That error about the fontPath is misleading. The rest of the error message tells what’s going on. It could not start Xvncserver.