X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=Documentation%2FDMA-API-HOWTO.txt;h=a0b6250add79c9c144fd1185fa91314febaa4241;hp=d568bc235bc008a215b981bcf303352c54bbda3a;hb=7f3bf7cd348cead84f8027b32aa30ea49fa64df5;hpb=67290f41b2715de0e0ae93c9285fcbe37ffc5b22

diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index d568bc235bc0..a0b6250add79 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -613,13 +613,13 @@ to use the dma_sync_*() interfaces.
 				pass_to_upper_layers(cp->rx_buf);
 				make_and_setup_new_rx_buf(cp);
 			} else {
-				/* Just sync the buffer and give it back
-				 * to the card.
+				/* CPU should not write to
+				 * DMA_FROM_DEVICE-mapped area,
+				 * so dma_sync_single_for_device() is
+				 * not needed here. It would be required
+				 * for DMA_BIDIRECTIONAL mapping if
+				 * the memory was modified.
 				 */
-				dma_sync_single_for_device(&cp->dev,
-							   cp->rx_dma,
-							   cp->rx_len,
-							   DMA_FROM_DEVICE);
 				give_rx_buf_to_card(cp);
 			}
 		}