Update on dma_buf Optimus support and EXPORT_SYMBOL drama?

I’ve been following the mailing lists and it seems that Alan Cox is only remaining objector to Nvidia using the dma_buf framework.

Can Nvidia move forward now?

I recall that if dma_buf usage was not permitted, there would be no binary support for Optimus on Linux at all.

Is this the case or would a clean room reverse engineering be possible?