path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2009-01-15 12:56:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-15 12:56:12 -0800
commit647df5189fecb2c2fa811421a3f28bf9034e3a70 (patch)
treef3fac52eedac2bb74a760a798ea8c397e2878553 /Documentation
parentcbbc49877d44408c4d0decf77c3c141732bbc679 (diff)
parent175add1981e53d22caba8f42d5f924a4de507b6c (diff)
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] SN specific version of dma_get_required_mask() [IA64] generic_defconfig: Enable SATA_VITESSE [IA64] dump stack on kernel unaligned warnings [IA64] Turn on CONFIG_HAVE_UNSTABLE_CLOCK [IA64] Update to use account_{steal,idle}_ticks
Diffstat (limited to 'Documentation')
1 files changed, 4 insertions, 5 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index b462bb14954..52441694fe0 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -170,16 +170,15 @@ Returns: 0 if successful and a negative error if not.
dma_get_required_mask(struct device *dev)
-After setting the mask with dma_set_mask(), this API returns the
-actual mask (within that already set) that the platform actually
-requires to operate efficiently. Usually this means the returned mask
+This API returns the mask that the platform requires to
+operate efficiently. Usually this means the returned mask
is the minimum required to cover all of memory. Examining the
required mask gives drivers with variable descriptor sizes the
opportunity to use smaller descriptors as necessary.
Requesting the required mask does not alter the current mask. If you
-wish to take advantage of it, you should issue another dma_set_mask()
-call to lower the mask again.
+wish to take advantage of it, you should issue a dma_set_mask()
+call to set the mask to the value returned.
Part Id - Streaming DMA mappings