Commit 0198d7bb8a ("ASoC: omap-mcbsp: Convert to use the sdma-pcm
instead of omap-pcm") resulted in broken audio playback on OMAP1510
(discovered on Amstrad Delta).
When running on OMAP1510, omap-pcm used to obtain DMA offset from
snd_dmaengine_pcm_pointer_no_residue() based on DMA interrupt triggered
software calculations instead of snd_dmaengine_pcm_pointer() which
depended on residue value calculated from omap_dma_get_src_pos().
Similar code path is still available in now used
sound/soc/soc-generic-dmaengine-pcm.c but it is not triggered.
It was verified already before that omap_get_dma_src_pos() from
arch/arm/plat-omap/dma.c didn't work correctly for OMAP1510 - see
commit 1bdd741991 ("ASoC: OMAP: fix OMAP1510 broken PCM pointer
callback") for details. Apparently the same applies to its successor,
omap_dma_get_src_pos() from drivers/dma/ti/omap-dma.c.
On the other hand, snd_dmaengine_pcm_pointer_no_residue() is described
as depreciated and discouraged for use in new drivers because of its
unreliable accuracy. However, it seems the only working option for
OPAM1510 now, as long as a software calculated residue is not
implemented as OMAP1510 fallback in omap-dma.
Using snd_dmaengine_pcm_pointer_no_residue() code path instead of
snd_dmaengine_pcm_pointer() in sound/soc/soc-generic-dmaengine-pcm.c
can be triggered in two ways:
- by passing pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE from
sound/soc/omap/sdma-pcm.c,
- by passing dma_caps.residue_granularity =
DMA_RESIDUE_GRANULARITY_DESCRIPTOR from DMA engine.
Let's do the latter.
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
- Updates to sprd, bam_dma, stm drivers.
- removal of VLAs in dmatest.
- Move TI drivers its own subdir.
- Switch to SPDX tags for ima/mxs dma drivers.
- Simplify getting .drvdata on bunch of drivers by Wolfram Sang.
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Merge tag 'dmaengine-4.18-rc1' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine updates from Vinod Koul:
- updates to sprd, bam_dma, stm drivers
- remove VLAs in dmatest
- move TI drivers to their own subdir
- switch to SPDX tags for ima/mxs dma drivers
- simplify getting .drvdata on bunch of drivers by Wolfram Sang
* tag 'dmaengine-4.18-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (32 commits)
dmaengine: sprd: Add Spreadtrum DMA configuration
dmaengine: sprd: Optimize the sprd_dma_prep_dma_memcpy()
dmaengine: imx-dma: Switch to SPDX identifier
dmaengine: mxs-dma: Switch to SPDX identifier
dmaengine: imx-sdma: Switch to SPDX identifier
dmaengine: usb-dmac: Document R8A7799{0,5} bindings
dmaengine: qcom: bam_dma: fix some doc warnings.
dmaengine: qcom: bam_dma: fix invalid assignment warning
dmaengine: sprd: fix an NULL vs IS_ERR() bug
dmaengine: sprd: Use devm_ioremap_resource() to map memory
dmaengine: sprd: Fix potential NULL dereference in sprd_dma_probe()
dmaengine: pl330: flush before wait, and add dev burst support.
dmaengine: axi-dmac: Request IRQ with IRQF_SHARED
dmaengine: stm32-mdma: fix spelling mistake: "avalaible" -> "available"
dmaengine: rcar-dmac: Document R-Car D3 bindings
dmaengine: sprd: Move DMA request mode and interrupt type into head file
dmaengine: sprd: Define the DMA data width type
dmaengine: sprd: Define the DMA transfer step type
dmaengine: ti: New directory for Texas Instruments DMA drivers
dmaengine: shdmac: Change platform check to CONFIG_ARCH_RENESAS
...
Janusz Krzysztofik