linux-kernel - Re: [PATCH] dmaengine: jz4780: Fix transfers being ACKed too soon

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Message-ID: <20190521043009.GK15118@vkoul-mobl>
Date:   Tue, 21 May 2019 10:00:09 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     Dan Williams <dan.j.williams@...el.com>, od@...c.me,
        dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dmaengine: jz4780: Fix transfers being ACKed too soon

On 04-05-19, 23:37, Paul Cercueil wrote:
> When a multi-descriptor DMA transfer is in progress, the "IRQ pending"
> flag will apparently be set for that channel as soon as the last
> descriptor loads, way before the IRQ actually happens. This behaviour
> has been observed on the JZ4725B, but maybe other SoCs are affected.
> 
> In the case where another DMA transfer is running into completion on a
> separate channel, the IRQ handler would then run the completion handler
> for our previous channel even if the transfer didn't actually finish.
> 
> Fix this by checking in the completion handler that we're indeed done;
> if not the interrupted DMA transfer will simply be resumed.

Applied, thanks

-- 
~Vinod