Lewis dot structures of CO2
It is almost always possible to draw resonance structures. In case of $\ce{CO2}$ you could imagine a resonance structure in which the carbon doesn't have an electron octet and a positive charge and one of the oxygen atoms carrying a negative charge.
You could also draw one in which the carbon is only connected via a single bound to each oxygen and carrying two positive charges while the two oxygens carry a negative charge each.  

You might come up with more of those structures.  

So the question you really wanna ask is whether these resonance structures have any real contribution to the actual bonding state of $\ce{CO2}$ and for that you will see that all of the described strucutures are highly unfavourable due to their energetic state. Therefore the normal Lewis-notation of $\ce{CO2}$ decribes the real bonding state pretty well as all other resonance structures don't contribute much.