Update kernel parameter document for libata DMA mode setting knobs.

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e5b447a0acda..c4178778e7fd 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -883,6 +883,14 @@ and is between 256 and 4096 characters. It is defined in the file
         lapic_timer_c2_ok       [X86-32,x86-64,APIC] trust the local apic timer in
                         C2 power state.
 
+        libata.dma=     [LIBATA] DMA control
+                        libata.dma=0      Disable all PATA and SATA DMA
+                        libata.dma=1      PATA and SATA Disk DMA only
+                        libata.dma=2      ATAPI (CDROM) DMA only
+                        libata.dma=4      Compact Flash DMA only 
+                        Combinations also work, so libata.dma=3 enables DMA
+                        for disks and CDROMs, but not CFs.
+
         libata.noacpi   [LIBATA] Disables use of ACPI in libata suspend/resume
                         when set.
                         Format: <int>