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-rw-r--r--Documentation/kernel-parameters.txt3
-rw-r--r--drivers/base/Kconfig3
2 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a126a31dde02..809e880bc787 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -656,7 +656,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Sets the size of kernel global memory area for
contiguous memory allocations and optionally the
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
cmo_free_hint= [PPC] Format: { yes | no }
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 134f763d90fd..61a33f4ba608 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -252,6 +252,9 @@ config DMA_CMA
to allocate big physically-contiguous blocks of memory for use with
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>.
If unsure, say "n".