I don't thinks XGI's Volari Z7/Z9 GPUs ever worked with xf86-video-sis driver. They have been supported by xf86-video-xgi driver (which is basically a fork of xf86-video-sis driver). IIRC we support it still on sle11, but removed support for sle12 and current openSUSE versions. Feel free to clone the xgi git repo and build it yourself. Maybe you're lucky. git://anongit.freedesktop.org/git/xorg/driver/xf86-video-xgi