I thought that only Imagination had this Z-discard IP? Has it been licensed out to all parties, or do they do something slightly differently? AFAIK, that was the sole thing that made their gpus both power efficient and fast (well, the two in this case being directly related).
Originally Posted by elanthis
I recall Imagination's ace card was tiled rendering, not Z tricks. HiZ has been in Radeons since ~8500.
Re: How to toggle HIZ?
It's now enabled by default in the git master. To disable it, set these environment variables.
Originally Posted by seandarcy
When running Mesa master, proceed with caution. In some OpenGL corner cases, HiZ causes some nasty bugs that we haven't solved yet.