neon instructions accessing framebuffer causes system freeze

Has anyone got mesa llvmpipe with neon acceleration working on BBB? When running kmscube with llvmpipe driver the whole system freeze. The only way to recover is a hard reset.

If I disable neon instructions everything works. If I patch tilcdc driver to use non-coherent (= cached) framebuffer everything works.

This thread suggests it is a power rail problem:

Looking at the forum link and note about 800Mhz, as a quick test, if you force the cpu governor to hold at 800Mhz vs performance (1Ghz) do you see any change?


I can see a slight improvement when lowering the clock speed down to 800Mhz. Perhaps 5-10 frames. Lowering to 300MHz gives me a few 100 frames.

Adding additional 47uF capacitors on the vdd_core and vdd_mpu rails does nothing to improve.