Hi Vinod, eDMA sullpies the data transmission service for other IPs, so it should be suspended later and resumed earlier. For example: Synchronous Audio Interface (SAI), SAI use DMA to transfer the data. When suspend: 1, SAI using suspend handlers to stop the DMA transmission. 2, DMA using suspend_late handlers to check whether DMA chan is idle. When resume: 1, DMA using resume_early to enable. And then can servicing for others. 2, SAI using resume and then can use DMA to data transmission. We must sure the order is right, so I think DMA should using early/late handlers. Thanks. Best Regards, Yuan Yao On Thursday, July 16, 2015 9:24 PM, Vinod wrote: > On Wed, Jul 15, 2015 at 05:32:58PM +0800, Yuan Yao wrote: > > + > > +static const struct dev_pm_ops fsl_edma_pm_ops = { > > + .suspend_late = fsl_edma_suspend_late, > > + .resume_early = fsl_edma_resume_early, > any reason why you are using early/late handlers? > > -- > ~Vinod -- 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