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From: Vinod Koul <vkoul@kernel.org>
To: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Pierre-Yves MORDRET <pierre-yves.mordret@st.com>,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org
Subject: Re: [PATCH] dmaengine: stm32-dma: fix residue calculation in stm32-dma
Date: Tue, 30 Apr 2019 22:48:56 +0530	[thread overview]
Message-ID: <20190430171856.GW3845@vkoul-mobl.Dlink> (raw)
In-Reply-To: <f7f28d56-a3e4-38a3-8580-b241fe0dcb49@st.com>

On 30-04-19, 16:58, Arnaud Pouliquen wrote:

> >> Hope that will help to clarify.
> > 
> > Yes that helps, maybe we should add these bits in code and changelog..
> > :)I will update the comments and commit message in a V2 in this way
> > 
> > And how does this impact non cyclic case where N descriptors maybe
> > issued. The driver seems to support non cyclic too...
> 
> Correct it supports SG as well, but double buffer mode is not used in
> such case. Hw is programmed under IT for every descriptors : no
> automatic register reloaded as in cyclic mode. We won't end up in the
> situation depicted below.

Okay sounds good then. Can you add a bit more of this in the code (this
was very helpful) not as a fix but documentation so that people (or you
down the line) will remember why this was done like this

Thanks

-- 
~Vinod

      reply	other threads:[~2019-04-30 17:19 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-27 12:21 Arnaud Pouliquen
2019-04-23 15:18 ` Arnaud Pouliquen
2019-04-24  9:26   ` Pierre Yves MORDRET
2019-04-26 12:17 ` Vinod Koul
2019-04-26 13:41   ` Arnaud Pouliquen
2019-04-29  5:13     ` Vinod Koul
2019-04-29 14:52       ` Arnaud Pouliquen
2019-04-30  8:22         ` Vinod Koul
2019-04-30 14:58           ` Arnaud Pouliquen
2019-04-30 17:18             ` Vinod Koul [this message]

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