[alsa-devel] [PATCH v2 03/15] dmaengine: Add no_wakeup parameter to dmaengine_prep_dma_cyclic()

Peter Ujfalusi peter.ujfalusi at ti.com
Fri Sep 14 11:28:28 CEST 2012


On 09/14/2012 11:50 AM, Vinod Koul wrote:
>> Well, the idea was that the driver would disable interrupts if there is no
>> callback to call, since there would be nothing to do in the interrupt
>> handler anyway. But I guess the flags approach should work fine as well.
> Yes we _could_ do that, but this relies on dmaengine driver to have this
> implicit understanding. Anyone using dmaengine library in ASoC may or
> may not be aware of this, so i would consider it hackish.
> Using this flag explicitly makes everyone aware what the intended
> behaviour is.

I'm not sure about which flags should ASoC set for the two case we are going
to have. I think it should be something like this:

unsigned long flags = DMA_CTRL_ACK;

if (!substream->runtime->no_period_wakeup)

I'm not 100% sure of the role of DMA_CTRL_ACK in this case. Or should we only
handle the DMA_PREP_INTERRUPT flag, like this:

unsigned long flags = 0;

if (!substream->runtime->no_period_wakeup)

What do you think?


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