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

[Lucas Stach]

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

Regards,
Lucas