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authorMark Brown <broonie@opensource.wolfsonmicro.com>2011-08-08 14:56:19 +0900
committerMark Brown <broonie@opensource.wolfsonmicro.com>2011-08-08 14:56:19 +0900
commit18d4ed4342c14ebeebe60d267b171053efcdfa87 (patch)
treef315e77f66cbb70869e2f80cde5c18380a80901e /Documentation/DMA-API-HOWTO.txt
parent722d0daf2b607a32dad1357bf797e3803484af0a (diff)
parent22de4534ae12d61257fc0e53d2571686b03305bc (diff)
Merge branch 'for-3.1' into for-3.2
Conflict due to the fix for the register map failure - taken the for-3.1 version. Conflicts: sound/soc/codecs/sgtl5000.c
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);
}
}