On Tue, 29 Jan 2008 22:56:14 -0800 David Brownell <[EMAIL PROTECTED]> wrote:
> On Tuesday 29 January 2008, Haavard Skinnemoen wrote: > > > > Btw, there's one issue I forgot to mention: I believe the DMA Engine > > framework is currently misusing the DMA mapping API, and this patchset > > makes things worse. > > > > Currently, the async_tx bits of the API do the required calls to > > dma_map_single() and/or dma_map_page(), but they rely on the driver to > > do the unmapping. This is problematic ... > > > > How do we solve this? > > How about: for peripheral DMA, don't let the engine see anything > except dma_addr_t values. I don't think it does, but the dma_addr_t value is enough to call dma_unmap_single() and dma_unmap_page(). > The engine needs to be able to dma_alloc_coherent() memory too, > which is pre-mapped. Right, which is another argument for not doing any unmapping in the DMA engine driver. We really need to push this responsibility to the client. Haavard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
