[alsa-devel] [PATCH] dmaengine: imx-sdma: advertise all supported slave bus widths

[Mark Brown]

On Fri, Oct 13, 2017 at 01:35:43PM +0200, Lucas Stach wrote:
> Am Freitag, den 13.10.2017, 12:25 +0100 schrieb Mark Brown:
> > On Fri, Oct 13, 2017 at 12:43:46PM +0200, Lucas Stach wrote:

> > > The commit [1] which changed imx-pcm-dma to derive the pcm_config from the
> > > attached dmaengine introduced a regression on the supported sample formats,
> > > as imx-sdma doesn't properly advertise all the supported slave bus widths.

> > How did this work previously - shouldn't we have failed to use the
> > unadvertised bus widths?  I'd expect the framework to be providing error
> > checking for the clients here.

> No, if the sound PCM implementation explicitly provides a pcm_config
> with the hw.formats set to 0, the core only looks at the DAI supported
> formats. Now that we derive the pcm_config from the dmaengine

I'm not talking about the sound side here...

> hw.formats gets filled with formats supported by the dmaengine, which
> is then used as an additional constraint by the core.

...I'm talking about the constraints supported on the DMA side.  I would
not expect the DMA side to be accepting things it said it didn't support.
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