[ewg] Re: [ofa-general] Toward next OFED release (1.3)

[Roland Dreier]

 > What about allowing to allocate coherent memory for CQ inside the kernel
 > to fix issue with Altix machines?

Sorry... I've been remiss in posting about this.  I would actually
prefer to see an extension to the dma_map_sg() interface (a new flag
perhaps?) that would set the right magic bit in the DMA address on
altix.  The refactoring of ib_umem_get() to be called by low-level
drivers makes this a fairly clean approach, and it avoids the problems
with using dma_alloc_coherent() to allocate userspace buffers (for
example, dma_alloc_coherent() uses up kernel virtual addresses, which
may be scarce on 32 bit architectures).

 - R.