Messages in this thread |  | | | Date | Wed, 11 Feb 2004 09:51:23 -0800 | | From | "David S. Miller" <> | | Subject | Re: [Patch] dma_sync_to_device |
On Wed, 11 Feb 2004 09:39:01 -0700 Deepak Saxena <dsaxena@plexity.net> wrote:
> If pci_dma_sync_single is for FROM_DEVICE only, than the direction > parameter should go away from it and the from > pci_dma_sync_to_device_single().
This is wrong. The direction parameter says what was done by the device/cpu for the DMA, this is needed by the port to know how to perform the pci_dma_sync_single et al. correctly.
For example, a port may have to do something different for FROM_DEVICE vs. TO_DEVICE to properly execute the pci_dma_sync_single() request.
MIPS (and seemingly ARM) are probably the best platforms by which to draw up the worst case scenerio for the implementation of these things :) and thus the optimizations made possible by certain combinations of request+direction. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |