2

I'm trying run Firefox headless with Xvfb in Debian 7.8.

I run Xvfb (I tried with +extension RANDR and -extension RANDR)

$ sudo Xvfb :10 -ac
[dix] Could not init font path element /usr/share/fonts/X11/cyrillic, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/100dpi/:unscaled, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/75dpi/:unscaled, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/Type1, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/100dpi, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/75dpi, removing from list!
[dix] Could not init font path element /var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType, removing from list!

I exported environment variable export DISPLAY=:10 and run firefox

$ firefox
Xlib:  extension "RANDR" missing on display ":10".

I'm using:

  • Debian 7.8
  • Mozilla Firefox 38.0.1~linuxmint1+betsy
  • Xvfb 2:1.12.4-6+deb7u6
2

There are two issues here why does firefox need RANDR and why does your virtual xserver not support it.

Let's start with little background on RANDR, it is primarily used for screen resizing and configuring multiple monitor setups.

From a firefox perspective the assumption that all Xservers support all extensions seems to be a bad idea. I would file a bugreport especially as if RANDR is not supported you can assume that the resolution of the screen does not change making fallback easy.

From the xserver perspective nothing would preclude you developing support for XRANDR for a virtual xserver there is little demand for it although it would be a reasonable wishlist item. On the other hand given that Xvfb does not provide Visuals for a quick hack you could just switch to a different xserver. There are several implementations of Xvnc which support XRANDR including Tigervnc. using vnc would not be quite as efficient given that it also includes a vnc server and http server, but it will just work and you don't have to actually see what it is doing, but you can if you want to.

1

On Debian RANDR extension was enabled in xvfb/2:1.18.0 uploaded to "unstable" in the end of January 2016.

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