This fix audio underrun issue. When SNDRV_PCM_TRIGGER_STOP and SNDRV_PCM_TRIGGER_START, it calls prepare again. buf_tail should be reset to zero. So move buf_tail initialization into prepare function. Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxxxxx> --- drivers/dma/imx-sdma.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index a472a29..def08f7 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -814,8 +814,6 @@ static int sdma_request_channel(struct sdma_channel *sdmac) init_completion(&sdmac->done); - sdmac->buf_tail = 0; - return 0; out: @@ -924,6 +922,8 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg( sdmac->flags = 0; + sdmac->buf_tail = 0; + dev_dbg(sdma->dev, "setting up %d entries for channel %d.\n", sg_len, channel); @@ -1024,6 +1024,8 @@ static struct dma_async_tx_descriptor *sdma_prep_dma_cyclic( sdmac->status = DMA_IN_PROGRESS; + sdmac->buf_tail = 0; + sdmac->flags |= IMX_DMA_SG_LOOP; sdmac->direction = direction; ret = sdma_load_context(sdmac); -- 1.7.5.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-arm-kernel