Messages in this thread | | | Date | Wed, 14 May 2014 14:24:29 +0200 | From | Lars-Peter Clausen <> | Subject | Re: [PATCH] dma: pl330: Add support for DMA_PAUSE command |
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On 05/14/2014 02:07 PM, Tushar Behera wrote: > On 14 May 2014 17:29, Jassi Brar <jassisinghbrar@gmail.com> wrote: >> On Wed, May 14, 2014 at 8:53 AM, Tushar Behera <tushar.behera@linaro.org> 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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