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>

4 files changed, 11 insertions, 1 deletions

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index 6061fb5f4e1c..c15682a2f9db 100644
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -206,4 +206,8 @@ config SND_PCM_XRUN_DEBUG
 config SND_VMASTER
         bool
 
+config SND_DMA_SGBUF
+        def_bool y
+        depends on X86
+
 source "sound/core/seq/Kconfig"
diff --git a/sound/core/Makefile b/sound/core/Makefile
index 4229052e7b91..350a08d277f4 100644
--- a/sound/core/Makefile
+++ b/sound/core/Makefile
@@ -13,7 +13,7 @@ snd-pcm-objs := pcm.o pcm_native.o pcm_lib.o pcm_timer.o pcm_misc.o \
                 pcm_memory.o
 
 snd-page-alloc-y := memalloc.o
-snd-page-alloc-$(CONFIG_HAS_DMA) += sgbuf.o
+snd-page-alloc-$(CONFIG_SND_DMA_SGBUF) += sgbuf.o
 
 snd-rawmidi-objs  := rawmidi.o
 snd-timer-objs    := timer.o
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 1b3534d67686..9e92441f9b78 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -199,6 +199,8 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size,
         case SNDRV_DMA_TYPE_DEV:
                 dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
                 break;
+#endif
+#ifdef CONFIG_SND_DMA_SGBUF
         case SNDRV_DMA_TYPE_DEV_SG:
                 snd_malloc_sgbuf_pages(device, size, dmab, NULL);
                 break;
@@ -269,6 +271,8 @@ void snd_dma_free_pages(struct snd_dma_buffer *dmab)
         case SNDRV_DMA_TYPE_DEV:
                 snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
                 break;
+#endif
+#ifdef CONFIG_SND_DMA_SGBUF
         case SNDRV_DMA_TYPE_DEV_SG:
                 snd_free_sgbuf_pages(dmab);
                 break;
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index a6d42808828c..caa7796bc2f5 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -304,6 +304,7 @@ int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
 
 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
 
+#ifdef CONFIG_SND_DMA_SGBUF
 /**
  * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
  * @substream: the pcm substream instance
@@ -349,6 +350,7 @@ unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
         return size;
 }
 EXPORT_SYMBOL(snd_pcm_sgbuf_get_chunk_size);
+#endif /* CONFIG_SND_DMA_SGBUF */
 
 /**
  * snd_pcm_lib_malloc_pages - allocate the DMA buffer