[alsa-devel] [PATCH] ASoC: dmaengine: add runtime status checking in dmaengine_pcm_dma_complete

Mark Brown broonie at kernel.org
Wed Jun 12 16:39:44 CEST 2013

On Wed, Jun 12, 2013 at 02:15:24PM +0200, Lars-Peter Clausen wrote:
> On 06/12/2013 09:43 AM, Vinod Koul wrote:

> > Yes you need to call dmaengine_terminate_all(). But even then we might have
> > trasaction in flight or some dma controllers cant abort immediately (need to
> > wait till FIFOs are flushed etc). In general it is a good practice to call
> > dma_sync_wait() before you tear down the client.
> > If you still see an issue, then it a buggy driver :)

> Even though if the driver can't abort the transfer immediately, I'd still
> expect to not see any calls to the descriptors callback after
> dmaengine_terminate_all() has been called.

It'd certainly be much less surprising - if something's terminated it
really oughtn't to be generating callbacks.

> We should probably still call dma_sync_wait() though before we free any of
> the DMA transfer buffers. But I guess this will open a whole new can of
> bugs, since none of the drivers actually seem to mark a descriptor as
> completed if the transfer is aborted using dmaengine_terminate_all()

Oh joy.
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