Note the first comment there shows that their EGLStreams implementation shipped with vsync broken. EGLStreams seems attractive to NVIDIA because it was easy to

Note the first comment there shows that their EGLStreams implementation shipped with vsync broken. EGLStreams seems attractive to NVIDIA because it was easy to implement (incorrectly). The features they talk about enabling on Tegra are not impossible with GBM, it just may involve adding a feature.