[PATCH] dmaengine: ti: k3-udma: Avoid false error msg on chan teardown

[Péter Ujfalusi]

Hi Vignesh,

On 15/02/2022 06:41, Vignesh Raghavendra wrote:
> In cyclic mode, there is no additional descriptor pushed to collect
> outstanding data on channel teardown. Therefore no need to wait for this
> descriptor to come back.
> 
> Without this terminating aplay cmd outputs false error msg like:
> [  116.402800] ti-bcdma 485c0100.dma-controller: chan1 teardown timeout!

are you sure it is aplay? It is MEM_TO_DEV, we only use the flush
descriptor for DEV_TO_MEM. MEM_TO_DEV can 'disconnect' from the
peripheral to flush out the FIFO.

I have not seen this on am654, j721e. I can not recall seeing this on
the capture side either.

The cyclic TR should be able to drain the DEV_TO_MEM by itself and the
TR should terminate.


> Signed-off-by: Vignesh Raghavendra <vigneshr at ti.com>
> ---
>  drivers/dma/ti/k3-udma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> index 9abb08d353ca0..c9a1b2f312603 100644
> --- a/drivers/dma/ti/k3-udma.c
> +++ b/drivers/dma/ti/k3-udma.c
> @@ -3924,7 +3924,7 @@ static void udma_synchronize(struct dma_chan *chan)
>  
>  	vchan_synchronize(&uc->vc);
>  
> -	if (uc->state == UDMA_CHAN_IS_TERMINATING) {
> +	if (uc->state == UDMA_CHAN_IS_TERMINATING && !uc->cyclic) {
>  		timeout = wait_for_completion_timeout(&uc->teardown_completed,
>  						      timeout);
>  		if (!timeout) {

-- 
Péter