This is related to https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1432949
With the upstream patch applied on mesa GPU compositors started working on my PowerMac 7,3.
This is related to https:/ /bugs.launchpad .net/ubuntu/ +source/ mesa/+bug/ 1432949
With the upstream patch applied on mesa GPU compositors started working on my PowerMac 7,3.