ALSA: Fix SG-buffer DMA with non-coherent architectures

Using SG-buffers with dma_alloc_coherent() is often very inefficient
on non-coherent architectures because a tracking record could be
allocated in addition for each dma_alloc_coherent() call.
Instead, simply disable SG-buffers but just allocate normal continuous
buffers on non-supported (currently all but x86) architectures.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index 7ccce94a5255..c42506212649 100644
--- a/include/sound/memalloc.h
+++ b/include/sound/memalloc.h
@@ -47,7 +47,11 @@ struct snd_dma_device {
 #define SNDRV_DMA_TYPE_UNKNOWN          0       /* not defined */
 #define SNDRV_DMA_TYPE_CONTINUOUS       1       /* continuous no-DMA memory */
 #define SNDRV_DMA_TYPE_DEV              2       /* generic device continuous */
+#ifdef CONFIG_SND_DMA_SGBUF
 #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
 
 /*
  * info for buffer allocation
@@ -60,6 +64,7 @@ struct snd_dma_buffer {
         void *private_data;     /* private for allocator; don't touch */
 };
 
+#ifdef CONFIG_SND_DMA_SGBUF
 /*
  * Scatter-Gather generic device pages
  */
@@ -107,6 +112,7 @@ static inline void *snd_sgbuf_get_ptr(struct snd_sg_buf *sgbuf, size_t offset)
 {
         return sgbuf->table[offset >> PAGE_SHIFT].buf + offset % PAGE_SIZE;
 }
+#endif /* CONFIG_SND_DMA_SGBUF */
 
 /* allocate/release a buffer */
 int snd_dma_alloc_pages(int type, struct device *dev, size_t size,