Messages in this thread | | | Date | Wed, 14 May 2014 17:37:03 +0530 | Subject | Re: [PATCH] dma: pl330: Add support for DMA_PAUSE command | From | Tushar Behera <> |
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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.
> DMA_PAUSE means freezing the transfer, not dropping it. DMA_RESUME > then moves the transfer again from that point. Clubbing PAUSE with > TERMINATE is plain wrong. Sorry. >
Would you please suggest how should we go ahead with implementing DMA_PAUSE/DMA_RESUME support for PL330 driver?
> Regards > Jassi
Thanks, -- Tushar Behera
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