Vinod, On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote: > The code to handle any length SG lists calls edma_resume() > even before edma_start() is called. This is incorrect > because edma_resume() enables edma events on the channel > after which CPU (in edma_start) cannot clear posted > events by writing to ECR (per the EDMA user's guide). > > Because of this EDMA transfers fail to start if due > to some reason there is a pending EDMA event registered > even before EDMA transfers are started. This can happen if > an EDMA event is a byproduct of device initialization. > > Fix this by calling edma_resume() only if it is not the > first batch of MAX_NR_SG elements. > > Without this patch, MMC/SD fails to function on DA850 EVM > with DMA. The behaviour is triggered by specific IP and > this can explain why the issue was not reported before > (example with MMC/SD on AM335x). > > Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card. > > Cc: stable@xxxxxxxxxxxxxxx # v3.12.x+ > Cc: Joel Fernandes <joelf@xxxxxx> > Acked-by: Joel Fernandes <joelf@xxxxxx> > Tested-by: Jon Ringle <jringle@xxxxxxxxxxxxx> > Tested-by: Alexander Holler <holler@xxxxxxxxxxxxx> > Reported-by: Jon Ringle <jringle@xxxxxxxxxxxxx> > Signed-off-by: Sekhar Nori <nsekhar@xxxxxx> Looks like this patch is not in mainline still? Thanks, Sekhar -- 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
