The latest fix for the non-contiguous memalloc helper changed the allocation method for a non-IOMMU system to use only the fallback allocator. This should have worked, but it caused a problem sometimes when too many non-contiguous pages are allocated that can't be treated by HD-audio controller.

As a quirk workaround, go back to the original strategy: use dma_alloc_noncontiguous() at first, and apply the fallback only when it fails, but only for non-IOMMU case.

We'll need a better fix in the fallback code as well, but this workaround should paper over most cases.

Fixes: 9736a325137b ("ALSA: memalloc: Don't fall back for SG-buffer with IOMMU") Reported-by: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/r/CAHk-=wgSH5ubdvt76gNwa004ooZAEJL_1Q-Fyw5M2FDdqL==d... Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/memalloc.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 6a81aaab25ab..ba095558b6d1 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -542,8 +542,10 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size) struct sg_table *sgt; void *p;

+ sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir, + DEFAULT_GFP, 0); #ifdef CONFIG_SND_DMA_SGBUF - if (!get_dma_ops(dmab->dev.dev)) { + if (!sgt && !get_dma_ops(dmab->dev.dev)) { if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG) dmab->dev.type = SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK; else @@ -551,9 +553,6 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size) return snd_dma_sg_fallback_alloc(dmab, size); } #endif - - sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir, - DEFAULT_GFP, 0); if (!sgt) return NULL;