Tearing down DMA transfer setup after DMA client has finished

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Vinod Koul <vinod.koul at intel.com> writes:

> On Fri, Dec 09, 2016 at 11:25:57AM +0100, Sebastian Frias wrote:
>> 
>> What concrete solution do you propose?
>
> I have already proposed two solutions.
>
> A) Request a channel only when you need it. Obviously we can't do virtual
> channels with this (though we should still use virt-channels framework).
> The sbox setup and teardown can be done as part of channel request and
> freeup. PL08x already does this.
>
> Downside is that we can only have as many consumers at a time as channels.
>
> I have not heard any technical reason for not doing this apart from drivers
> grab the channel at probe, which is incorrect and needs to be fixed
> irrespective of the problem at hand.
>
> This is my preferred option.

Sorry, but this is not acceptable.

> B) Create a custom driver specific API. This API for example:
> 	sbox_setup(bool enable, ...)
> can be called by client to explicitly setup and clear up the sbox setting.
>
> This way we can have transactions muxed.
>
> I have not heard any arguments on why we shouldn't do this except Russell's
> comment that A) solves this.

Driver-specific interfaces are not the solution.  That way lies chaos
and madness.

This would all be so much easier if you all would just shut up for a
moment and let me fix it properly.

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