Re: [PATCH v4 2/2] dmaengine: add a driver for AMBA AXI NBPF DMAC IP cores

Hi Vinod,

On Mon, 28 Jul 2014, Guennadi Liakhovetski wrote:

quoted

Looking at the code again, I think we need to free irq (you can call
devm_free_irq()) and call syncronize_irq so that anything pending is
flushed.  So if you can send follow up patch doing these in .remove, we can
merge these

This is a nice offer, thanks! But to accept it I'd like to understand: why 
do you think we need that? In my previous email I presented to you a 
theoretical and improbable race situation, that I can foresee. You erased 
it in your reply, but it was dealing with the 
.device_free_chan_resources() method, so, your suspected race is a 
different one. Could you please explain to me, why do you think interrupts 
are possible during .release()? Aren't all channels guaranteed to have 
been freed by that time?

It would be great to get an explanation for your comment, please? How can 
interrupts come after all channels have been freed? Or how can .release() 
be called while some channels are still in use?

Thanks
Guennadi
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