Commit f0d6d1f6 authored by Jean Delvare's avatar Jean Delvare Committed by Linus Torvalds

CMA: document cma=0

It isn't obvious that CMA can be disabled on the kernel's command line, so
document it.
Signed-off-by: default avatarJean Delvare <jdelvare@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 86cf78d7
...@@ -656,7 +656,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. ...@@ -656,7 +656,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Sets the size of kernel global memory area for Sets the size of kernel global memory area for
contiguous memory allocations and optionally the contiguous memory allocations and optionally the
placement constraint by the physical address range of placement constraint by the physical address range of
memory allocations. For more information, see memory allocations. A value of 0 disables CMA
altogether. For more information, see
include/linux/dma-contiguous.h include/linux/dma-contiguous.h
cmo_free_hint= [PPC] Format: { yes | no } cmo_free_hint= [PPC] Format: { yes | no }
......
...@@ -252,6 +252,9 @@ config DMA_CMA ...@@ -252,6 +252,9 @@ config DMA_CMA
to allocate big physically-contiguous blocks of memory for use with to allocate big physically-contiguous blocks of memory for use with
hardware components that do not support I/O map nor scatter-gather. hardware components that do not support I/O map nor scatter-gather.
You can disable CMA by specifying "cma=0" on the kernel's command
line.
For more information see <include/linux/dma-contiguous.h>. For more information see <include/linux/dma-contiguous.h>.
If unsure, say "n". If unsure, say "n".
......
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