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. > 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 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
