[PATCH] drm/vc4: Add threading support

From: Jonas Pfeil Add support for threaded fragment shaders. The validation code checks for thread switch signals and ensures that the registers of the other thread are not touched, and that our clamps are not live across thread switches. It also checks that the threading

[PATCH] drm/vc4: Add threading support

From: Jonas Pfeil Add support for threaded fragment shaders. The validation code checks for thread switch signals and ensures that the registers of the other thread are not touched, and that our clamps are not live across thread switches. It also checks that the threading and branching