After installing the ATI Radeon legacy drivers (version 13.1) Unity no longer starts in 3D mode, where it did before. I can select "Ubuntu" during login, and indeed it is the default choice, but when I do login Unity loads 2D mode instead of 3D mode. I cannot get Unity to start in 3D at all, even after running unity --reset.
The output of lscpi | grep VGA is as follows:
01:05.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RS880M [Mobility Radeon HD 4225/4250]
I tried some of the solutions in the post Damien mentioned below, including reverting back to open source drivers. No luck, as
returns "Not software rendered" as "no". But unity 3d had always worked until just the other day. So how do I get it to software render?