linux/arch/powerpc
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 [POWERPC] Celleb: basic support 2007-02-07 14:03:21 +11:00
configs [POWERPC] pasemi: defconfig 2007-02-07 14:03:22 +11:00
kernel [PATCH] powerpc vDSO: use install_special_mapping 2007-02-09 09:25:47 -08:00
lib [POWERPC] Use ARRAY_SIZE macro when appropriate 2007-02-08 16:08:18 +11:00
math-emu [POWERPC] ppc math-emu needs -fno-builtin-fabs for math.c and fabs.c 2006-09-26 15:24:35 +10:00
mm [POWERPC] Remove bogus comment about page_is_ram 2007-02-08 16:08:43 +11:00
oprofile [POWERPC] Oprofile cleanup 2007-02-07 14:03:19 +11:00
platforms [PATCH] powerpc: celleb trivial endianness and iomem annotations 2007-02-09 09:14:08 -08:00
sysdev [POWERPC] Assign all PCI busses on G3 Blue & White 2007-02-07 14:03:22 +11:00
xmon [PATCH] arch/powerpc trivial annotations 2007-02-09 09:14:06 -08:00
.gitignore [POWERPC] Add files build to .gitignore 2006-12-04 20:41:29 +11:00
Kconfig [PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA 2007-02-11 10:51:19 -08:00
Kconfig.debug [POWERPC] pasemi: UART udbg support 2007-02-07 14:03:22 +11:00
Makefile [POWERPC] Create a "wrapper" script and use it in arch/powerpc/boot 2006-09-28 14:30:02 +10:00