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kernel.org; dkim=none (message not signed) header.d=none;kernel.org; dmarc=bestguesspass action=none header.from=cern.ch; Received-SPF: Pass (protection.outlook.com: domain of cern.ch designates 188.184.36.46 as permitted sender) receiver=protection.outlook.com; client-ip=188.184.36.46; helo=cernmxgwlb4.cern.ch; Received: from cernmxgwlb4.cern.ch (188.184.36.46) by AM5EUR02FT020.mail.protection.outlook.com (10.152.8.125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.1580.10 via Frontend Transport; Fri, 8 Feb 2019 15:30:46 +0000 Received: from cernfe03.cern.ch (188.184.36.39) by cernmxgwlb4.cern.ch (188.184.36.46) with Microsoft SMTP Server (TLS) id 14.3.408.0; Fri, 8 Feb 2019 16:30:43 +0100 Received: from cwe-513-vol689.cern.ch (188.185.69.206) by smtp.cern.ch (188.184.36.52) with Microsoft SMTP Server (TLS) id 14.3.408.0; Fri, 8 Feb 2019 16:30:43 +0100 From: Federico Vaga To: Vinod Koul , Jonathan Corbet CC: , , , Federico Vaga Subject: [PATCH] doc:dmaengine: clarify DMA desc. pointer after submission Date: Fri, 8 Feb 2019 16:30:38 +0100 Message-ID: <20190208153038.23272-1-federico.vaga@cern.ch> X-Mailer: git-send-email 2.15.0 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [188.185.69.206] X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:188.184.36.46;IPV:NLI;CTRY:CH;EFV:NLI;SFV:NSPM;SFS:(10001)(10009020)(459900002);DIR:OUT;SFP:1101;SCL:1;SRVR:HE1PR0601MB2266;H:cernmxgwlb4.cern.ch;FPR:;SPF:None;LANG:en; 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Signed-off-by: Federico Vaga --- Documentation/driver-api/dmaengine/client.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst index fbbb2831f29f..d728e50105eb 100644 --- a/Documentation/driver-api/dmaengine/client.rst +++ b/Documentation/driver-api/dmaengine/client.rst @@ -168,6 +168,13 @@ The details of these operations are: dmaengine_submit() will not start the DMA operation, it merely adds it to the pending queue. For this, see step 5, dma_async_issue_pending. + .. note:: + + After calling ``dmaengine_submit()`` the submitted transfer descriptor + (``struct dma_async_tx_descriptor``) belongs to the DMA engine. + Consequentially, the client must consider invalid the pointer to that + descriptor. + 5. Issue pending DMA requests and wait for callback notification The transactions in the pending queue can be activated by calling the -- 2.15.0