To improve latency with cyclic DMA operation it is preferred to use different eventq/tc than the default which is used by all other drivers (mmc, spi, i2c, etc). When preparing the cyclic dma ask for non default queue for the channel which is going to be used with cyclic mode. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx> --- drivers/dma/edma.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 1dd9e8806975..10048b40fac8 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -628,6 +628,9 @@ static struct dma_async_tx_descriptor *edma_prep_dma_cyclic( edesc->pset[i].opt |= TCINTEN; } + /* Use different eventq/tc for cyclic DMA to reduce latency */ + edma_request_non_default_queue(echan->ch_num); + return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags); } -- 1.9.1 -- 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
