From: Jean Delvare <jdelvare@suse.de>
Date: Thu, 9 Oct 2014 22:29:41 +0000 (-0700)
Subject: CMA: document cma=0
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f0d6d1f6ff6f8525cfa396ec1969b8f402391445;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

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: Jean 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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".