Re: [PATCH] dma: pl330: Add support for DMA_PAUSE command

[Lars-Peter Clausen]

On 05/14/2014 02:07 PM, Tushar Behera wrote:
> On 14 May 2014 17:29, Jassi Brar <jassisinghbrar@xxxxxxxxx> wrote:
> > On Wed, May 14, 2014 at 8:53 AM, Tushar Behera <tushar.behera@xxxxxxxxxx> wrote:
> > > While playing back audio, pmc_dmaengine requests the DMA channel to
> > > stop DMA transmission through DMA_PAUSE command.
> > >
> > > Currently PL330 driver doesn't support DMA pause command, leaving
> > > the DMA state inconsistent when the system resumes. Instead, it would
> > > be better to terminate the DMA transfer during suspend and restart
> > > again during resume.
> > >
> > > Tested with audio playback across a suspend-resume cycle.
> > What is pmc_dmaengine? How does DMA_PAUSE help, when there is no DMA_RESUME?
>
> Sorry, it is a typo.
>
> sound/core/pcm_dmaengine.c:snd_dmaengine_pcm_trigger() -->
> dmaengine_pause() is called during system suspend.

It is only called if the DMA driver has support for pausing and resuming DMA 
transfers. Or at least that is the intention.

- Lars
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