At Tue, 26 Aug 2008 15:01:18 -0600, Grant Grundler wrote: > > On Tue, Aug 26, 2008 at 05:25:24PM +0200, Takashi Iwai wrote: > ... > > Now updated my git tree: > > http://git.kernel.org/?p=linux/kernel/git/tiwai/sound-2.6.git;a=shortlog;h=topic/dma-fix > > I'll post each patch again if preferred. > > +#ifdef CONFIG_SND_COHERENT_DMA > #define SNDRV_DMA_TYPE_DEV_SG 3 /* generic device SG-buffer */ > +#else > +#define SNDRV_DMA_TYPE_DEV_SG SNDRV_DMA_TYPE_DEV /* no SG-buf support */ > +#endif > > Hi Takashi, > I had to look at a previous patch to figure out CONFIG_SND_COHERENT_DMA > is an arch dependent flag: > > +config SND_COHERENT_DMA > + def_bool y > + depends on !PPC32 || !NOT_COHERENT_CACHE > + depends on !ARM > + depends on !MIPS > + depends on !PARISC > > In general, I don't expect this to be a compile time option. Right now it has to be a compile-time option because - dma_mmap_coherent() isn't implemented in every architecture (thus fails to build), and - pages allocated via dma_mmap_coherent() aren't always suitable for SG-mapping. > I'm wondering if extending the DMA API to provide an > interface for user space to also be DMA coherent. Yes, this would be really nice. > Maybe something to talk about at Linux Plumbers Conf > or kernel summit... Agreed. > > Do you guys see any pending issues? I'd love to merge these patches > > into the upstream for 2.6.28. > > SPARC/SPARC64 usually falls into the same category as parisc/mips. Right. I guess SH*, too. But, a missing piece doesn't mean to stop pushing this :) We can implement on other archs occasionally based on the existing works. thanks, Takashi
