The patch titled Documentation/DMA-API-HOWTO.txt: fix misleading example has been added to the -mm tree. Its filename is documentation-dma-api-howtotxt-fix-misleading-example.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: Documentation/DMA-API-HOWTO.txt: fix misleading example From: Michal Miroslaw <mirq-linux@xxxxxxxxxxxx> See: DMA-API.txt, part Id, DMA_FROM_DEVICE description. Signed-off-by: Michal Miroslaw <mirq-linux@xxxxxxxxxxxx> Cc: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/DMA-API-HOWTO.txt | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff -puN Documentation/DMA-API-HOWTO.txt~documentation-dma-api-howtotxt-fix-misleading-example Documentation/DMA-API-HOWTO.txt --- a/Documentation/DMA-API-HOWTO.txt~documentation-dma-api-howtotxt-fix-misleading-example +++ a/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); } } _ Patches currently in -mm which might be from mirq-linux@xxxxxxxxxxxx are linux-next.patch documentation-dma-api-howtotxt-fix-misleading-example.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html