[PATCH 5.19 037/192] ALSA: hda: Once again fix regression of page allocations with IOMMU

Greg Kroah-Hartman
2022-09-13T14:11:44Z

From: Takashi Iwai <tiwai@suse.de>

commit 37137ec26c2c03039d8064c00f6eae176841ee0d upstream.

The last fix for trying to recover the regression on AMD platforms,
unfortunately, leaded to yet another regression: it turned out that
IOMMUs don't like the usage of raw page allocations.

This is yet another attempt for addressing the log saga; at this time,
we re-use the existing buffer allocation mechanism with SG-pages
although we require only single pages. The SG buffer allocation
itself was confirmed to work for stream buffers, so it's relatively
easy to adapt for other places.

The only problem is: although the HD-audio code is accessing the
address directly via dmab->address field, SG-pages don't set up it.
For the ease of adaption, we now set up the dmab->addr field from the
address of the first page as default, so that it can run with the
HD-audio driver code as-is without the excessive call of
snd_sgbuf_get_addr() multiple times; that's the only change in the
memalloc helper side. The rest is nothing but a flip of the dma_type
field in the HD-audio side.

Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again")
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/CABXGCsO+kB2t5QyHY-rUe76npr1m0-5JOtt8g8SiHUo34ur7Ww@mail.gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216112
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216363
Link: https://lore.kernel.org/r/20220906090319.23358-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/core/memalloc.c | 9 +++++++--
sound/pci/hda/hda_intel.c | 2 +-
2 files changed, 8 insertions(+), 3 deletions(-)

--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -535,10 +535,13 @@ static void *snd_dma_noncontig_alloc(str
dmab->dev.need_sync = dma_need_sync(dmab->dev.dev,
sg_dma_address(sgt->sgl));
p = dma_vmap_noncontiguous(dmab->dev.dev, size, sgt);
- if (p)
+ if (p) {
dmab->private_data = sgt;
- else
+ /* store the first page address for convenience */
+ dmab->addr = snd_sgbuf_get_addr(dmab, 0);
+ } else {
dma_free_noncontiguous(dmab->dev.dev, size, sgt, dmab->dev.dir);
+ }
return p;
}

@@ -772,6 +775,8 @@ static void *snd_dma_sg_fallback_alloc(s
if (!p)
goto error;
dmab->private_data = sgbuf;
+ /* store the first page address for convenience */
+ dmab->addr = snd_sgbuf_get_addr(dmab, 0);
return p;

error:
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1817,7 +1817,7 @@ static int azx_create(struct snd_card *c

/* use the non-cached pages in non-snoop mode */
if (!azx_snoop(chip))
- azx_bus(chip)->dma_type = SNDRV_DMA_TYPE_DEV_WC;
+ azx_bus(chip)->dma_type = SNDRV_DMA_TYPE_DEV_WC_SG;

if (chip->driver_type == AZX_DRIVER_NVIDIA) {
dev_dbg(chip->card->dev, "Enable delay in RIRB handling\n");