Then the next step would be to fake sg-buffer from this straight buffer. Revert the above, and modify sgbuf.c to the following:
- Allocate a large continuous buffer
- Assign each page in this large buffer
If this still works, it's not about vmap, but it just means that the physically ordered pages do matter -- implicitly showing that the snooping behavior isn't properly turned on / off on the controller.
To fake SG-buffer, I did this test: restore all the codes to the original, then added some codes in snd_malloc_sgbuf_pages() like below, the result is badly niose.
Not really what I meant. Rather something like below (totally untested).
[Hans :] I know what you mean now and complete code like below, but the result is still noise.
Thanks,
Hans ---
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c index 84fffabdd129..643f6cb2048c 100644 --- a/sound/core/sgbuf.c +++ b/sound/core/sgbuf.c @@ -68,7 +68,7 @@ void *snd_malloc_sgbuf_pages(struct device *device, size_t *res_size) { struct snd_sg_buf *sgbuf; -unsigned int i, pages, chunk, maxpages; +unsigned int i, pages, chunk; struct snd_dma_buffer tmpb; struct snd_sg_page *table; struct page **pgtable; @@ -90,38 +90,18 @@ void *snd_malloc_sgbuf_pages(struct device *device, goto _failed; sgbuf->page_table = pgtable;
-/* allocate pages */ -maxpages = MAX_ALLOC_PAGES; -while (pages > 0) { -chunk = pages; -/* don't be too eager to take a huge chunk */ -if (chunk > maxpages) -chunk = maxpages; -chunk <<= PAGE_SHIFT; -if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device, - chunk, &tmpb) < 0) { -if (!sgbuf->pages) -goto _failed; -if (!res_size) -goto _failed; -size = sgbuf->pages * PAGE_SIZE; -break; -} -chunk = tmpb.bytes >> PAGE_SHIFT; -for (i = 0; i < chunk; i++) { -table->buf = tmpb.area; -table->addr = tmpb.addr; -if (!i) -table->addr |= chunk; /* mark head */ -table++; -*pgtable++ = virt_to_page(tmpb.area); -tmpb.area += PAGE_SIZE; -tmpb.addr += PAGE_SIZE; -} -sgbuf->pages += chunk; -pages -= chunk; -if (chunk < maxpages) -maxpages = chunk; +if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, device, size, &tmpb) < 0) +goto _failed; +chunk = tmpb.bytes >> PAGE_SHIFT; +for (i = 0; i < pages; i++) { +table->buf = tmpb.area; +table->addr = tmpb.addr; +if (!i) +table->addr |= pages; /* mark head */ +table++; +*pgtable++ = virt_to_page(tmpb.area); +tmpb.area += PAGE_SIZE; +tmpb.addr += PAGE_SIZE; +sgbuf->pages += chunk; }
sgbuf->size = size;
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