Gpu

You might be familiar with mesamatrix - a nice site to track the state of all GPU drivers provided by Mesa. Ohh.. did I say all? Let’s have a closer look: This page is a graphical representation of the text file docs/features.txt from the Mesa repository. So wouldn’t it be sick to get etnaviv mentioned in docs/features.txt and onto the matrix? First mesamatrix needs to know/support etnaviv. This seems to be quite simple as there is already a pull request to add a bunch of embedded GPU drivers: Add VC4,VC5 and Vivante GPUs...

After years of hard work the etnaviv team reached an other very important milestone. The gallium driver and the renderonly library got pushed into mesa’s git repository and will be released with mesa 17.0 - yeah! This does not mean we are done with development at all. There are many interesting topics to work on and some of them like better support for newer IP cores or a reworked GLSL compiler should see the light of day during the next months....

Last Friday I got kmscube successfully running with mesa and the new etnaviv DRM kernel driver. At this time I got it not really pixel perfect and I spend some nights to get it fixed. It turns out that I need a small mesa hack to get the rendering correct. You may ask why did it so long to get it working? Let me explain it to you. The Vivnate GPU is a so called render-only GPU which does not have any kind of scanout logic in it....

It took me some time to rework the device tree bindings but it looks like it starts to work! View the code on [Gist](https://gist.github.com/austriancoder/6196fa33011a120a01dd54dbd077a60d).Gets loaded into : [ 3.358155] vivante: module is from the staging directory, the quality is unknown, you have been warned. [ 3.373087] imx-sgtl5000 sound.15: sgtl5000 2028000.ssi mapping ok [ 3.379150] [drm] add child gpu2d [ 3.379154] [drm] add child gpu3d [ 3.380395] vivante-gpu 134000.gpu2d: pre gpu[idx]: 0x00000000 [ 3....

I did spend quite some time the last days to figure out how the MMU v1 could work and what all the code in the v4 Kernel sources does. It took quite some time and a little hint from Russel to finally understand it. So lets start with the technical details. The MMU uses a page table with a maximum size of 256KB. Where each Page Table Entry (PTE) is 4 byte long....