Re: PCI DMA to small buffers on cache-incoherent arch

Oliver Neukum
2002-06-10T17:22:56Z

> > So is the consensus now that in general drivers should make sure any
> > buffers passed to pci_map/unmap are aligned to SMP_CACHE_BYTES (and a
> > multiple of SMP_CACHE_BYTES in size)? In other words if a driver uses
> > an unaligned buffer it should be fixed unless we can prove (and
> > document in a comment :) that it won't cause problems on an arch
> > without cache coherency and with a writeback cache.
>
> And how about we don't call it SMP_CACHE_BYTES too? The processors
> where this matters certainly aren't doing SMP...

Definitely we should call it something different so we can limit it to
architectures that need it.

Regards
Oliver