I use Ubuntu 16.04 with a Radeon HD 7770. I knew there will be no hardware 3D acceleration but ... it also crashes with software rendering with an illegal instruction in "swrast.dri". What do you recommend? Do you think upgrading Mesa will help? I use the original version 18.0.5.
At least, it would be nice to have 2D acceleration and a working 3D software rendering on Radeon SI cards.