linux/arch/alpha
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 kbuild: introduce utsrelease.h 2006-07-03 23:30:54 +02:00
kernel PCI: make isa_bridge Alpha-only 2007-02-07 15:50:06 -08:00
lib [NET]: Alpha checksum annotations and cleanups. 2006-12-02 21:23:01 -08:00
math-emu Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mm [PATCH] mm: arch do_page_fault() vs in_atomic() 2006-12-07 08:39:21 -08:00
oprofile [PATCH] oprofile: Fix unnecessary cleverness 2006-06-26 09:58:17 -07:00
defconfig [PATCH] update all defconfigs for ARCH_DISCONTIGMEM_ENABLE 2005-06-23 09:45:02 -07:00
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 kbuild: alpha,x86_64 use generic asm-offsets.h support 2005-09-09 21:28:48 +02:00