At Wed, 14 Apr 2010 17:00:19 +0800, Wu Zhangjin wrote: > > On Wed, 2010-04-14 at 08:31 +0200, Takashi Iwai wrote: > [...] > > > > > > Before, we have added the low-level handling with pgprot_noncached() in > > > snd_pcm_mmap() to fix it, but now, can we add MIPS specific > > > dma_mmap_coherent() as ARM did? > > > > That would be a certainly fix, yes. I have no objection, of course ;) > > A quicky, less-intrusive one would be the patch below. > > The below patch works well, just tested it. Thanks. But, I remember vaguely that calling pgprot_noncached() unconditionally is dangerous. It should be checked somehow, e.g. via platform_device_is_coherent(). And, this found only in dma-coherence.h, and adding it to pcm_native.c would become messy like below... So, it'd be really better to add dma_mmap_coherent(), indeed. Takashi --- diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index c22ebb0..4c3edc1 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -36,6 +36,9 @@ #include <sound/timer.h> #include <sound/minors.h> #include <asm/io.h> +#if defined(CONFIG_MIPS) && defined(CONFIG_DMA_NONCOHERENT) +#include <dma-coherence.h> +#endif /* * Compatibility @@ -3188,6 +3191,10 @@ static int snd_pcm_default_mmap(struct snd_pcm_substream *substream, substream->runtime->dma_area, substream->runtime->dma_addr, area->vm_end - area->vm_start); +#elif defined(CONFIG_MIPS) && defined(CONFIG_DMA_NONCOHERENT) + if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV && + !plat_device_is_coherent(substream->dma_buffer.dev.dev)) + area->vm_page_prot = pgprot_noncached(area->vm_page_prot); #endif /* ARCH_HAS_DMA_MMAP_COHERENT */ /* mmap with fault handler */ area->vm_ops = &snd_pcm_vm_ops_data_fault;
