On 14 May 2014 17:54, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote: > 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 During suspend, snd_dmaengine_pcm_trigger():SNDRV_PCM_TRIGGER_SUSPEND is called which unconditionally calls dmaengine_pause(). Should we update snd_dmaengine_pcm_trigger() to check for DMA pause/resume support and call dmaengine_pause() or dmaengine_terminate_all() accordingly? -- 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
