From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Yuan Yao <yao.yuan@freescale.com>
Cc: vinod.koul@intel.com, robh+dt@kernel.org,
dan.j.williams@intel.com, mark.rutland@arm.com,
shawnguo@kernel.org, leoyang.li@nxp.com,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, Yuan Yao <yao.yuan@nxp.com>
Subject: Re: [PATCH v1 1/5] dma: Add QorIQ qDMA engine driver support
Date: Thu, 18 Aug 2016 10:16:03 +0100 [thread overview]
Message-ID: <20160818091603.GT1041@n2100.armlinux.org.uk> (raw)
In-Reply-To: <1471502328-28305-2-git-send-email-yao.yuan@freescale.com>
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."
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2016-08-18 9:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-18 6:38 [PATCH v1 0/5] dma: Add QorIQ qDMA engine driver support Yuan Yao
2016-08-18 6:38 ` [PATCH v1 1/5] " Yuan Yao
2016-08-18 9:16 ` Russell King - ARM Linux [this message]
2016-08-24 3:39 ` Yao Yuan
2016-08-23 12:18 ` kbuild test robot
2016-08-23 12:18 ` [PATCH] dma: fix platform_no_drv_owner.cocci warnings kbuild test robot
2016-08-18 6:38 ` [PATCH v1 2/5] dma: Add device tree binding for QorIQ qDMA driver Yuan Yao
2016-08-18 6:38 ` [PATCH v1 3/5] MAINTAINERS: add maintainer entry for QorIQ QDMA driver Yuan Yao
2016-08-18 6:38 ` [PATCH v1 4/5] ARM: dts: ls1043a: add qDMA node Yuan Yao
2016-08-29 7:29 ` Alexander Stein
2016-08-29 7:34 ` Alexander Stein
2016-08-31 4:17 ` Yao Yuan
2016-08-18 6:38 ` [PATCH v1 5/5] ARM: dts: ls1021a: " Yuan Yao
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