From: vinod.koul@intel.com (Vinod Koul)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] dmaengine: pxa_dma: fix hotchain corner case
Date: Fri, 19 Aug 2016 12:02:24 +0530 [thread overview]
Message-ID: <20160819063224.GU9681@localhost> (raw)
In-Reply-To: <1470596509-1726-1-git-send-email-robert.jarzmik@free.fr>
On Sun, Aug 07, 2016 at 09:01:48PM +0200, Robert Jarzmik wrote:
> In the case where a descriptor is chained on a running channel, and as
> explained in the comment in the code 10 lines above, the success of the
> chaining is ensured either if :
> - the DMA is still running
> - or if the chained transfer is completed
>
> Unfortunately the transfer completness test was done on the descriptor
> to which the transfer was chained, and not the transfer being chained at
> the end, ie. hot-chained.
>
> This corner case is extremely hard to trigger, as usually the DMA chain
> is still running, and the first case takes care of returning success of
> the hot-chaining. It was seen by hot-chaining several "small transfers"
> to a running "big transfer", not in a real-life usecase but by testing
> the robustness of the driver.
Applied, thanks
--
~Vinod
WARNING: multiple messages have this Message-ID (diff)
From: Vinod Koul <vinod.koul@intel.com>
To: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Daniel Mack <daniel@zonque.org>,
Haojian Zhuang <haojian.zhuang@gmail.com>,
linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dmaengine: pxa_dma: fix hotchain corner case
Date: Fri, 19 Aug 2016 12:02:24 +0530 [thread overview]
Message-ID: <20160819063224.GU9681@localhost> (raw)
In-Reply-To: <1470596509-1726-1-git-send-email-robert.jarzmik@free.fr>
On Sun, Aug 07, 2016 at 09:01:48PM +0200, Robert Jarzmik wrote:
> In the case where a descriptor is chained on a running channel, and as
> explained in the comment in the code 10 lines above, the success of the
> chaining is ensured either if :
> - the DMA is still running
> - or if the chained transfer is completed
>
> Unfortunately the transfer completness test was done on the descriptor
> to which the transfer was chained, and not the transfer being chained at
> the end, ie. hot-chained.
>
> This corner case is extremely hard to trigger, as usually the DMA chain
> is still running, and the first case takes care of returning success of
> the hot-chaining. It was seen by hot-chaining several "small transfers"
> to a running "big transfer", not in a real-life usecase but by testing
> the robustness of the driver.
Applied, thanks
--
~Vinod
next prev parent reply other threads:[~2016-08-19 6:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-07 19:01 [PATCH] dmaengine: pxa_dma: fix hotchain corner case Robert Jarzmik
2016-08-07 19:01 ` Robert Jarzmik
2016-08-07 19:01 ` [PATCH] dmaengine: pxa_dma: fix debug message Robert Jarzmik
2016-08-07 19:01 ` Robert Jarzmik
2016-08-19 6:32 ` Vinod Koul [this message]
2016-08-19 6:32 ` [PATCH] dmaengine: pxa_dma: fix hotchain corner case Vinod Koul
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