Highmem issues with MMC filesystem

[Russell King - ARM Linux]

On Wed, Mar 17, 2010 at 10:58:48AM -0400, Nicolas Pitre wrote:
> On Wed, 17 Mar 2010, Hemanth V wrote:
> > Nicolas, Russel are there any more details available which might help
> > in investigating this further.
> 
> The only conclusion I came to so far is that ARMv5 where highmem works 
> just fine in all cases has VIVT cache whereas ARMv6 has VIPT cache.  
> And the problem with VIPT caches occurs when direct DMA is involved, 
> otherwise there is no problem if PIO or NFS is used.  Sprinkling some 
> flush_cache_all() in a few places makes things work, but this is not a 
> satisfactory solution.

This sounds like the problem we had with the DMA API.  Since that's now
fixed, there shouldn't be a problem with the latest (-rc) kernels, or
a kernel with my old streaming DMA patches applied.