2017-11-14: VC5 GL, VC4 MADVISE, VC4 backports

Another series of VC5 GL features this week:

  • Occlusion query support.
  • Transform feedback’s queries mostly supported.
  • Fixed GL_OUT_OF_MEMORY (and OOMing the python runner!) on piglit’s streaming-texture-leak.
  • Fixed 8/16-bit integer texturing.

For VC4, the big news is that we’ve landed Boris’s MADVISE support in Mesa as well now. This means that if you have a 4.15 kernel and the next release of Mesa, the kernel will now be able to clean up the userspace BO cache when we run out of CMA. This doesn’t prevent all GL_OUT_OF_MEMORY errors, but it should reduce the circumstances where you can hit them.

I spent a while putting together a backport of all our kernel development for Raspbian’s rpi-4.9.y branch. So much has happened in DRM in the last year, that it’s getting harder and harder to backport our work. However, the PR I sent brings in fully functional support for the DSI panel (no more purple flickering!) and fix for a longstanding race that could crash the kernel when powering down the GPU (thanks to Stefan Schake for debugging and providing a patch!)

I also fixed the VC4 build and armhf cross-builds with the new meson build system, after Timothy Arceri noted that it wasn’t working on his Pi. I’m now happily using meson for all of my Mesa development.