> I am a bit perplexed about what powerpc has to do with GPUs.
As others note that IBM is funding most of the work, my guess is the main use-case here is IBM's POWER-based HPC clusters that have PowerPC CPUs augmented by a bunch of GPU coprocessors for Cuda/OpenCL offloading. IBM is trying to position POWER clusters as competing with x86-based clusters for certain kinds of work (especially scientific computing), and to match x86-based clusters decked out with GPUs they probably need to have GPU options for their POWER-based clusters as well.
The idea, as I read it (have not had occasion to encounter it myself) is that things are a lot easier if your CPU and GPU have the same endianness, or else you have to byte-swap whenever transferring data to/from the GPU (and there are even more complications if you have unified memory spaces). Since most (all?) commercially available GPUs are little-endian, if you want PowerPC CPUs along with GPUs for auxiliary processing, and want the endianness matched, the little-endian mode of PowerPC becomes important.
As others note that IBM is funding most of the work, my guess is the main use-case here is IBM's POWER-based HPC clusters that have PowerPC CPUs augmented by a bunch of GPU coprocessors for Cuda/OpenCL offloading. IBM is trying to position POWER clusters as competing with x86-based clusters for certain kinds of work (especially scientific computing), and to match x86-based clusters decked out with GPUs they probably need to have GPU options for their POWER-based clusters as well.
The idea, as I read it (have not had occasion to encounter it myself) is that things are a lot easier if your CPU and GPU have the same endianness, or else you have to byte-swap whenever transferring data to/from the GPU (and there are even more complications if you have unified memory spaces). Since most (all?) commercially available GPUs are little-endian, if you want PowerPC CPUs along with GPUs for auxiliary processing, and want the endianness matched, the little-endian mode of PowerPC becomes important.