Re: [RFC] generic device DMA implementation

From: David S. Miller (davem@redhat.com)
Date: Fri Dec 06 2002 - 13:17:15 EST


   From: "Adam J. Richter" <adam@yggdrasil.com>
   Date: Fri, 6 Dec 2002 08:19:25 -0800

           Under the API addition that we've been discussing, the
   extra cache flushes and invalidations that these drivers need
   would become macros that would be expand to nothing on the
   other architectures, and the drivers would no longer have to
   have "if (consistent_alloation_failed) ..." branches around them.

Ok, but here is where my big concerns lie.

Specifically, it took years to get most developers confortable with
pci_alloc_consitent() and friends. I totally fear that asking them to
now add cache flushing stuff to their drivers takes the complexity way
over the edge.

Willy, these PCXS/T processors sound like a newer cpu, do you mean to
tell me the caches are totally not coherent with device bus space?

Please elaborate, I want to learn more.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sat Dec 07 2002 - 22:00:27 EST