From 3ad796cbc36a7bc8bfd4de191d791b9490bc112b Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 15 Jun 2020 18:00:45 +0200 Subject: ALSA: pcm: Use SG-buffer only when direct DMA is available The DMA-coherent SG-buffer is tricky to use, as it does need the mapping. It used to work stably on x86 over years (and that's why we had enabled SG-buffer on solely x86) with the default mmap handler and vmap(), but our luck seems no forever success. The chance of breakage is high when the special DMA handling is introduced in the arch side. In this patch, we change the buffer allocation to use the SG-buffer only when the device in question is with the direct DMA. It's a bit hackish, but it's currently the only condition that may work (more or less) reliably with the default mmap and vmap() for mapping the pages that are deduced via virt_to_page(). In theory, we can apply the similar hack in the sound/core memory allocation helper, too; but it's used by SOF for allocating SG pages without re-mapping via vmap() or mmap, and it's fine to use it in that way, so let's keep it and adds the workaround in PCM side. Link: https://lore.kernel.org/r/20200615160045.2703-5-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/core/pcm_memory.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'sound/core/pcm_memory.c') diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c index 860935e3aea4..8326d16d3596 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -39,6 +40,18 @@ static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, if (max_alloc_per_card && card->total_pcm_alloc_bytes + size > max_alloc_per_card) return -ENOMEM; + + if (IS_ENABLED(CONFIG_SND_DMA_SGBUF) && + (type == SNDRV_DMA_TYPE_DEV_SG || type == SNDRV_DMA_TYPE_DEV_UC_SG) && + !dma_is_direct(get_dma_ops(dev))) { + /* mutate to continuous page allocation */ + dev_dbg(dev, "Use continuous page allocator\n"); + if (type == SNDRV_DMA_TYPE_DEV_SG) + type = SNDRV_DMA_TYPE_DEV; + else + type = SNDRV_DMA_TYPE_DEV_UC; + } + err = snd_dma_alloc_pages(type, dev, size, dmab); if (!err) { mutex_lock(&card->memory_mutex); -- cgit v1.2.3-70-g09d2 From 467fd0e82b6265b8e6cc078a70bd7592574d5c83 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 7 Jul 2020 13:12:25 +0200 Subject: ALSA: pcm: Fix build error on m68k and others The commit 3ad796cbc36a ("ALSA: pcm: Use SG-buffer only when direct DMA is available") introduced a check of the DMA type and this caused a build error on m68k (and possibly some others) due to the lack of dma_is_direct() definition. Since the check is needed only for CONFIG_SND_DMA_SGBUF enablement (i.e. solely x86), use #ifdef instead of IS_ENABLED() for avoiding such a build error. Fixes: 3ad796cbc36a ("ALSA: pcm: Use SG-buffer only when direct DMA is available") Reported-by: kernel test robot Link: https://lore.kernel.org/r/20200707111225.26826-1-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/core/pcm_memory.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'sound/core/pcm_memory.c') diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c index 8326d16d3596..795af1b88051 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -41,8 +41,9 @@ static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, card->total_pcm_alloc_bytes + size > max_alloc_per_card) return -ENOMEM; - if (IS_ENABLED(CONFIG_SND_DMA_SGBUF) && - (type == SNDRV_DMA_TYPE_DEV_SG || type == SNDRV_DMA_TYPE_DEV_UC_SG) && + +#ifdef CONFIG_SND_DMA_SGBUF + if ((type == SNDRV_DMA_TYPE_DEV_SG || type == SNDRV_DMA_TYPE_DEV_UC_SG) && !dma_is_direct(get_dma_ops(dev))) { /* mutate to continuous page allocation */ dev_dbg(dev, "Use continuous page allocator\n"); @@ -51,6 +52,7 @@ static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, else type = SNDRV_DMA_TYPE_DEV_UC; } +#endif /* CONFIG_SND_DMA_SGBUF */ err = snd_dma_alloc_pages(type, dev, size, dmab); if (!err) { -- cgit v1.2.3-70-g09d2 From 7d50b295c4af16f814ee82369c4a234df5228801 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 17 Jul 2020 08:41:30 +0200 Subject: Revert "ALSA: pcm: Use SG-buffer only when direct DMA is available" This reverts commit 3ad796cbc36a ("ALSA: pcm: Use SG-buffer only when direct DMA is available") also the modification commit 467fd0e82b62 ("ALSA: pcm: Fix build error on m68k and others"). Poking the DMA internal helper is a layer violation, so we should avoid that. Meanwhile the actual bug has been addressed by the Kconfig fix in commit dbed452a078d ("dma-pool: decouple DMA_REMAP from DMA_COHERENT_POOL"), so we can live without this hack. Link: https://lore.kernel.org/r/20200717064130.22957-1-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/core/pcm_memory.c | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'sound/core/pcm_memory.c') diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c index 795af1b88051..1bf6a3d9e0c2 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include #include @@ -41,19 +40,6 @@ static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, card->total_pcm_alloc_bytes + size > max_alloc_per_card) return -ENOMEM; - -#ifdef CONFIG_SND_DMA_SGBUF - if ((type == SNDRV_DMA_TYPE_DEV_SG || type == SNDRV_DMA_TYPE_DEV_UC_SG) && - !dma_is_direct(get_dma_ops(dev))) { - /* mutate to continuous page allocation */ - dev_dbg(dev, "Use continuous page allocator\n"); - if (type == SNDRV_DMA_TYPE_DEV_SG) - type = SNDRV_DMA_TYPE_DEV; - else - type = SNDRV_DMA_TYPE_DEV_UC; - } -#endif /* CONFIG_SND_DMA_SGBUF */ - err = snd_dma_alloc_pages(type, dev, size, dmab); if (!err) { mutex_lock(&card->memory_mutex); -- cgit v1.2.3-70-g09d2