RE: [PATCH v1 1/5] dma: Add QorIQ qDMA engine driver support

From	Yao Yuan <yao.yuan@nxp.com>
Newsgroups	linux.kernel
Subject	RE: [PATCH v1 1/5] dma: Add QorIQ qDMA engine driver support
Date	2016-08-24 09:20 +0200
Message-ID	<s9ADE-7nn-11@gated-at.bofh.it> (permalink)
References	<s7rEt-6bL-5@gated-at.bofh.it> <s7rEt-6bL-7@gated-at.bofh.it> <s7rEt-6bL-3@gated-at.bofh.it>
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On Thu, Aug 18, 2016 at 05:16 PM +0800, Russell King wrote:
> On Thu, Aug 18, 2016 at 02:38:44PM +0800, Yuan Yao wrote:
> > +			spin_lock(&fsl_comp->qchan->vchan.lock);
> > +			if (status == DMA_COMPLETE)
> > +				vchan_cookie_complete(&fsl_comp->vdesc);
> > +			fsl_comp->qchan->status = status;
> 
> This is buggy - if the DMA has finished processing it, even if it finished in error, it
> must _complete_ the transaction.  Completion is not the same as being
> successful - it means that the DMA is no longer processing the cookie.
> 
> The issue here is that when the _following_ transaction completes successfully,
> _this_ transaction will effectively be marked as complete due to the way the
> cookie system works.
> 
> So... to get this straight - "completion" means "I have finished processing this
> transaction".  It does not mean "I successfully processed this transaction
> without any errors."
> 

Thanks for your review.
So you mean that I should call vchan_cookie_complete no matter whether the error issue in QDMA?
I have some random DMA error test case, it seems work will.

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Re: [PATCH v1 1/5] dma: Add QorIQ qDMA engine driver support Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-08-18 11:20 +0200
  RE: [PATCH v1 1/5] dma: Add QorIQ qDMA engine driver support Yao Yuan <yao.yuan@nxp.com> - 2016-08-24 09:20 +0200

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