Intel HD Audio: sound stops working in Xen PV dom0 in >=5.17
Takashi Iwai
tiwai at suse.de
Tue Jan 17 08:58:57 CET 2023
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 at suse.de>
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@suse.de
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
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
More information about the Alsa-devel
mailing list