linux/arch/sparc
Christoph Lameter 5ac6da669e [PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA
As Andi pointed out: CONFIG_GENERIC_ISA_DMA only disables the ISA DMA
channel management.  Other functionality may still expect GFP_DMA to
provide memory below 16M.  So we need to make sure that CONFIG_ZONE_DMA is
set independent of CONFIG_GENERIC_ISA_DMA.  Undo the modifications to
mm/Kconfig where we made ZONE_DMA dependent on GENERIC_ISA_DMA and set
theses explicitly in each arches Kconfig.

Reviews must occur for each arch in order to determine if ZONE_DMA can be
switched off.  It can only be switched off if we know that all devices
supported by a platform are capable of performing DMA transfers to all of
memory (Some arches already support this: uml, avr32, sh sh64, parisc and
IA64/Altix).

In order to switch ZONE_DMA off conditionally, one would have to establish
a scheme by which one can assure that no drivers are enabled that are only
capable of doing I/O to a part of memory, or one needs to provide an
alternate means of performing an allocation from a specific range of memory
(like provided by alloc_pages_range()) and insure that all drivers use that
call.  In that case the arches alloc_dma_coherent() may need to be modified
to call alloc_pages_range() instead of relying on GFP_DMA.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:19 -08:00
..
boot Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kernel [PATCH] sanitize sections for sparc32 smp 2007-02-01 16:17:06 -08:00
lib [SPARC]: Make bitops use same spinlocks as atomics. 2006-12-17 16:18:47 -08:00
math-emu kbuild: use relative path to -I 2006-04-04 16:56:10 +02:00
mm [SPARC]: Check kzalloc() return value in SUN4D irq/iommu init. 2006-12-10 02:40:10 -08:00
oprofile [SPARC]: Add sparc profiling support 2006-10-17 19:28:53 -07:00
prom [SPARC]: Kill prom_getname, unused and not implemented properly. 2006-07-21 14:17:55 -07:00
defconfig [SPARC]: Update defconfig. 2006-12-17 14:21:34 -08:00
Kconfig [PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA 2007-02-11 10:51:19 -08:00
Kconfig.debug Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile [SPARC]: Add sparc profiling support 2006-10-17 19:28:53 -07:00