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authorJiri Kosina <jkosina@suse.cz>2011-09-15 15:08:05 +0200
committerJiri Kosina <jkosina@suse.cz>2011-09-15 15:08:18 +0200
commite060c38434b2caa78efe7cedaff4191040b65a15 (patch)
tree407361230bf6733f63d8e788e4b5e6566ee04818 /Documentation/DMA-API-HOWTO.txt
parent10e4ac572eeffe5317019bd7330b6058a400dfc2 (diff)
parentcc39c6a9bbdebfcf1a7dee64d83bf302bc38d941 (diff)
Merge branch 'master' into for-next
Fast-forward merge with Linus to be able to merge patches based on more recent version of the tree.
Diffstat (limited to 'Documentation/DMA-API-HOWTO.txt')
-rw-r--r--Documentation/DMA-API-HOWTO.txt12
1 files changed, 6 insertions, 6 deletions
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);
}
}