On Mon, 16 Jan 2023 16:55:11 +0100, Takashi Iwai wrote: > > On Tue, 27 Dec 2022 16:26:54 +0100, > Marek Marczykowski-Górecki wrote: > > > > On Thu, Dec 22, 2022 at 09:09:15AM +0100, Takashi Iwai wrote: > > > On Sat, 10 Dec 2022 17:17:42 +0100, > > > Marek Marczykowski-Górecki wrote: > > > > > > > > On Sat, Dec 10, 2022 at 02:00:06AM +0100, Marek Marczykowski-Górecki wrote: > > > > > On Fri, Dec 09, 2022 at 01:40:15PM +0100, Marek Marczykowski-Górecki wrote: > > > > > > On Fri, Dec 09, 2022 at 09:10:19AM +0100, Takashi Iwai wrote: > > > > > > > On Fri, 09 Dec 2022 02:27:30 +0100, > > > > > > > Marek Marczykowski-Górecki wrote: > > > > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > Under Xen PV dom0, with Linux >= 5.17, sound stops working after few > > > > > > > > hours. pavucontrol still shows meter bars moving, but the speakers > > > > > > > > remain silent. At least on some occasions I see the following message in > > > > > > > > dmesg: > > > > > > > > > > > > > > > > [ 2142.484553] snd_hda_intel 0000:00:1f.3: Unstable LPIB (18144 >= 6396); disabling LPIB delay counting > > > > > > > > > > Hit the issue again, this message did not appear in the log (or at least > > > > > not yet). > > > > > > > > > > (...) > > > > > > > > > > > > In anyway, please check the behavior with 6.1-rc8 + the commit > > > > > > > cc26516374065a34e10c9a8bf3e940e42cd96e2a > > > > > > > ALSA: memalloc: Allocate more contiguous pages for fallback case > > > > > > > from for-next of my sound git tree (which will be in 6.2-rc1). > > > > > > > > > > This did not helped. > > > > > > > > > > > Looking at the mentioned commits, there is one specific aspect of Xen PV > > > > > > that may be relevant. It configures PAT differently than native Linux. > > > > > > Theoretically Linux adapts automatically and using proper API (like > > > > > > set_memory_wc()) should just work, but at least for i915 driver it > > > > > > causes issues (not fully tracked down yet). Details about that bug > > > > > > report include some more background: > > > > > > https://lore.kernel.org/intel-gfx/Y5Hst0bCxQDTN7lK@mail-itl/ > > > > > > > > > > > > Anyway, I have tested it on a Xen modified to setup PAT the same way as > > > > > > native Linux and the audio issue is still there. > > > > > > > > > > > > > If the problem persists, another thing to check is the hack below > > > > > > > works. > > > > > > > > > > Trying this one now. > > > > > > > > And this one didn't either :/ > > > > > > (Sorry for the late reply, as I've been off in the last weeks.) > > > > > > I think the hack doesn't influence on the PCM buffer pages, but only > > > about BDL pages. Could you check the patch below instead? > > > It'll disable the SG-buffer handling on x86 completely. > > > > This seems to "fix" the issue, thanks! > > I guess I'll run it this way for now, but a proper solution would be > > nice. Let me know if I can collect any more info that would help with > > that. > > Then we seem to go back again with the coherent memory allocation for > the fallback sg cases. It was changed because the use of > dma_alloc_coherent() caused a problem with IOMMU case for retrieving > the page addresses, but since the commit 9736a325137b, we essentially > avoid the fallback when IOMMU is used, so it should be fine again. > > Let me know if the patch like below works for you instead of the > previous hack to disable SG-buffer (note: totally untested!) Gah, there was an obvious typo, scratch that. Below is a proper patch. Please try this one instead. thanks, Takashi -- 8< -- From: Takashi Iwai <tiwai@xxxxxxx> Subject: [PATCH] ALSA: memalloc: Use coherent DMA allocation for fallback again We switched the memory allocation for fallback cases in the noncontig type to use the standard alloc_pages*() at the commit a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again"), while we used the dma_alloc_coherent() in the past. The reason was that the page address retrieved from the virtual pointer returned from dma_alloc_coherent() can't be used with IOMMU systems. Meanwhile, we explicitly disabled the fallback allocation for IOMMU systems at the commit 9736a325137b ("ALSA: memalloc: Don't fall back for SG-buffer with IOMMU") after the commit above; that is, the usage of dma_alloc_coherent() should be OK again. Now, we've received reports that the current fallback page allocation caused a regression on Xen (and maybe other) systems; the sound disappear partially or completely. The further investigation showed that this can be worked around by the dma_alloc_coherent() pages. So, it's time to take it back. This patch switches back to the dma_alloc_coherent() for the fallback allocations. Unlike the previous implementation, the allocation is implemented in a more optimized way to try larger chunks. The page count is stored in the lower bits of the addresses. Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again") Fixes: 9736a325137b ("ALSA: memalloc: Don't fall back for SG-buffer with IOMMU") Link: https://lore.kernel.org/r/87tu256lqs.wl-tiwai@xxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> --- sound/core/memalloc.c | 44 +++++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 81025f50a542..dff07cd6f209 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -719,17 +719,30 @@ static const struct snd_malloc_ops snd_dma_sg_wc_ops = { struct snd_dma_sg_fallback { size_t count; struct page **pages; + dma_addr_t *addrs; }; static void __snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab, struct snd_dma_sg_fallback *sgbuf) { - bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK; - size_t i; - - for (i = 0; i < sgbuf->count && sgbuf->pages[i]; i++) - do_free_pages(page_address(sgbuf->pages[i]), PAGE_SIZE, wc); + size_t i, size; + + if (sgbuf->pages && sgbuf->addrs) { + i = 0; + while (i < sgbuf->count) { + if (!sgbuf->pages[i] || !sgbuf->addrs[i]) + break; + size = sgbuf->addrs[i] & ~PAGE_MASK; + if (WARN_ON(!size)) + break; + dma_free_coherent(dmab->dev.dev, size, + page_address(sgbuf->pages[i]), + sgbuf->addrs[i] & PAGE_MASK); + i += size; + } + } kvfree(sgbuf->pages); + kvfree(sgbuf->addrs); kfree(sgbuf); } @@ -738,9 +751,8 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size) struct snd_dma_sg_fallback *sgbuf; struct page **pagep, *curp; size_t chunk, npages; - dma_addr_t addr; + dma_addr_t *addrp; void *p; - bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK; sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL); if (!sgbuf) @@ -748,14 +760,16 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size) size = PAGE_ALIGN(size); sgbuf->count = size >> PAGE_SHIFT; sgbuf->pages = kvcalloc(sgbuf->count, sizeof(*sgbuf->pages), GFP_KERNEL); - if (!sgbuf->pages) + sgbuf->addrs = kvcalloc(sgbuf->count, sizeof(*sgbuf->addrs), GFP_KERNEL); + if (!sgbuf->pages || !sgbuf->addrs) goto error; pagep = sgbuf->pages; - chunk = size; + addrp = sgbuf->addrs; + chunk = (PAGE_SIZE - 1) << PAGE_SHIFT; /* to fit in low bits in addrs */ while (size > 0) { chunk = min(size, chunk); - p = do_alloc_pages(dmab->dev.dev, chunk, &addr, wc); + p = dma_alloc_coherent(dmab->dev.dev, chunk, addrp, DEFAULT_GFP); if (!p) { if (chunk <= PAGE_SIZE) goto error; @@ -767,6 +781,8 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size) size -= chunk; /* fill pages */ npages = chunk >> PAGE_SHIFT; + *addrp |= npages; /* store in lower bits */ + addrp += npages; curp = virt_to_page(p); while (npages--) *pagep++ = curp++; @@ -775,6 +791,10 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size) p = vmap(sgbuf->pages, sgbuf->count, VM_MAP, PAGE_KERNEL); if (!p) goto error; + + if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK) + set_pages_array_wc(sgbuf->pages, sgbuf->count); + dmab->private_data = sgbuf; /* store the first page address for convenience */ dmab->addr = snd_sgbuf_get_addr(dmab, 0); @@ -787,7 +807,11 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size) static void snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab) { + struct snd_dma_sg_fallback *sgbuf = dmab->private_data; + vunmap(dmab->area); + if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK) + set_pages_array_wb(sgbuf->pages, sgbuf->count); __snd_dma_sg_fallback_free(dmab, dmab->private_data); } -- 2.35.3
