On Thu, 26 Aug 2010 10:01:52 +0300 Marin Mitov <mitov@xxxxxxxxxxx> wrote: > > If you add something to the videobuf-dma-contig API, that's fine by me > > because drivers/media/video/videobuf-dma-contig.c uses the own > > structure and plays with dma_alloc_coherent. As long as a driver > > doesn't touch device->dma_mem directly, it's fine, > > Why, my understanding is that device->dma_mem is designed exactly for keeping > some chunk of coherent memory for device's private use via dma_alloc_from_coherent() > (and that is what dt3155v4l driver is using it for). I don't think so. device->dma_mem can be accessed only via the DMA-API. I think that the DMA-API says that dma_declare_coherent_memory declares coherent memory that can be access exclusively by a certain device. It's not for reserving coherent memory that can be used for any device for a device. Anway, you don't need coherent memory. So using the API for coherent memory isn't a good idea. > > There are already some workarounds for > > contigous memory in several drivers anyway. > > Sure, can these workarounds be exposed as API for general use? I don't think that's a good idea. Adding temporary workaround to the generic API and removing it soon after that doesn't sound a good developing maner. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
