I'm facing RANDR missing problem with Xvfb and firefox. Some people suggested Xvfb :1 -extension RANDR can solve the problem. But I found a also +extension option. In my environment(CentOS6.5), the ...
per the answer to this question, I'm running Xvfb to make a virtual display so firefox will run on my CentOS server. (I don't need to see firefox or do any actual key or screen input/output with ...