[{"id":811,"web_url":"https://patchwork.libcamera.org/comment/811/","msgid":"<20190213154153.GF5332@pendragon.ideasonboard.com>","date":"2019-02-13T15:41:53","subject":"Re: [libcamera-devel] [PATCH v2 3/8] libcamera: v4l2_device:\n\tstreamOff() when releasing buffers","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Kieran,\n\nThank you for the patch.\n\nOn Wed, Feb 13, 2019 at 03:10:22PM +0000, Kieran Bingham wrote:\n> We must ensure that the stream is disabled before releasing buffers. It will\n> not hurt to call streamOff() even if it is already off before releasing any\n> buffers back to the device.\n\nI'm not sure about this one. Doesn't it indicate a problem in the caller\ninstead ?\n\n> Signed-off-by: Kieran Bingham \n> ---\n> src/libcamera/v4l2_device.cpp | 2 ++\n> 1 file changed, 2 insertions(+)\n> \n> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp\n> index 23c0da295905..83073c28b817 100644\n> --- a/src/libcamera/v4l2_device.cpp\n> +++ b/src/libcamera/v4l2_device.cpp\n> @@ -642,6 +642,8 @@ int V4L2Device::releaseBuffers()\n> {\n> \tLOG(V4L2, Debug) << \"Releasing bufferPool\";\n> \n> +\tstreamOff();\n> +\n> \trequestBuffers(0);\n> \tbufferPool_ = nullptr;\n>","headers":{"Return-Path":"","Received":["from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 1AB4C610AE\n\tfor ;\n\tWed, 13 Feb 2019 16:41:57 +0100 (CET)","from pendragon.ideasonboard.com\n\t(dfj612yhrgyx302h3jwwy-3.rev.dnainternet.fi\n\t[IPv6:2001:14ba:21f5:5b00:ce28:277f:58d7:3ca4])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id A8FD285;\n\tWed, 13 Feb 2019 16:41:56 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1550072516;\n\tbh=Grub9jKpLxowYwvZjw4DEtAFWwRolNQEpCLHKc/bkBc=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=KvbmfwqNVF8rb6NQqGoo1gbyMAuQSLA21nG9RP2GDvdJS3818MvXY9HDnghOPegx3\n\tE1fjKL9+FGdJLYfqVbg0BQyRVwue8hVIvA4SMwM11JjBlC4ZkZSEMAMC/alv6OAzwj\n\t3uR8bnmfg/PyihoWWS8BQ0356ltDrWMXmhifpfc4=","Date":"Wed, 13 Feb 2019 17:41:53 +0200","From":"Laurent Pinchart ","To":"Kieran Bingham ","Cc":"LibCamera Devel ","Message-ID":"<20190213154153.GF5332@pendragon.ideasonboard.com>","References":"<20190213151027.6376-1-kieran.bingham@ideasonboard.com>\n\t<20190213151027.6376-4-kieran.bingham@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20190213151027.6376-4-kieran.bingham@ideasonboard.com>","User-Agent":"Mutt/1.10.1 (2018-07-13)","Subject":"Re: [libcamera-devel] [PATCH v2 3/8] libcamera: v4l2_device:\n\tstreamOff() when releasing buffers","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.23","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Wed, 13 Feb 2019 15:41:57 -0000"}},{"id":819,"web_url":"https://patchwork.libcamera.org/comment/819/","msgid":"","date":"2019-02-13T16:30:36","subject":"Re: [libcamera-devel] [PATCH v2 3/8] libcamera: v4l2_device:\n\tstreamOff() when releasing buffers","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Hi Laurent,\n\nOn 13/02/2019 15:41, Laurent Pinchart wrote:\n> Hi Kieran,\n> \n> Thank you for the patch.\n> \n> On Wed, Feb 13, 2019 at 03:10:22PM +0000, Kieran Bingham wrote:\n>> We must ensure that the stream is disabled before releasing buffers. It will\n>> not hurt to call streamOff() even if it is already off before releasing any\n>> buffers back to the device.\n> \n> I'm not sure about this one. Doesn't it indicate a problem in the caller\n> instead ?\n\nPerhaps. It means (in the cases that I've hit) that the error paths have\nnot called streamOff().\n\nIs it more preferable to leave buffers 'un-released'?\n\nPerhaps would you prefer to see releaseBuffers return an error if it\nfails? As this is likely to be on cleanup paths, and destruction - what\nwould you expect the application to do in the event of failure to\nreleaseBuffers? (I guess - fix their code...)\n\n\nEither way - I'll just drop this patch for now.\n\n--\nKieran\n\n\n>> Signed-off-by: Kieran Bingham \n>> ---\n>> src/libcamera/v4l2_device.cpp | 2 ++\n>> 1 file changed, 2 insertions(+)\n>>\n>> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp\n>> index 23c0da295905..83073c28b817 100644\n>> --- a/src/libcamera/v4l2_device.cpp\n>> +++ b/src/libcamera/v4l2_device.cpp\n>> @@ -642,6 +642,8 @@ int V4L2Device::releaseBuffers()\n>> {\n>> \tLOG(V4L2, Debug) << \"Releasing bufferPool\";\n>> \n>> +\tstreamOff();\n>> +\n>> \trequestBuffers(0);\n>> \tbufferPool_ = nullptr;\n>> \n>","headers":{"Return-Path":"","Received":["from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 6F817610AE\n\tfor ;\n\tWed, 13 Feb 2019 17:30:39 +0100 (CET)","from [192.168.0.21]\n\t(cpc89242-aztw30-2-0-cust488.18-1.cable.virginm.net [86.31.129.233])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id C151B85;\n\tWed, 13 Feb 2019 17:30:38 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1550075438;\n\tbh=X7LRrAWzBBzbky2B31CzL4DoDXINTTIx9W5oRJlHvlI=;\n\th=Reply-To:Subject:To:Cc:References:From:Date:In-Reply-To:From;\n\tb=AZX1x61J7qxbUXjGEUt/BMyUSkGUSfa/Z67k6p3kyQwRvZeTFbIdN7HDZoHipshrh\n\tKibT1OThikASRKpyNl+rnnO8zrWVK4nluZNifwKZ4c+mb4m6sfbk0NyxaqXUc2C1Bi\n\tXsq1F3JIRsRgw2EQGheZIN9Sf8ZO+YFiMY6m/n0U=","Reply-To":"kieran.bingham@ideasonboard.com","To":"Laurent Pinchart ","Cc":"LibCamera Devel ","References":"<20190213151027.6376-1-kieran.bingham@ideasonboard.com>\n\t<20190213151027.6376-4-kieran.bingham@ideasonboard.com>\n\t<20190213154153.GF5332@pendragon.ideasonboard.com>","From":"Kieran Bingham ","Openpgp":"preference=signencrypt","Autocrypt":"addr=kieran.bingham@ideasonboard.com; keydata=\n\tmQINBFYE/WYBEACs1PwjMD9rgCu1hlIiUA1AXR4rv2v+BCLUq//vrX5S5bjzxKAryRf0uHat\n\tV/zwz6hiDrZuHUACDB7X8OaQcwhLaVlq6byfoBr25+hbZG7G3+5EUl9cQ7dQEdvNj6V6y/SC\n\trRanWfelwQThCHckbobWiQJfK9n7rYNcPMq9B8e9F020LFH7Kj6YmO95ewJGgLm+idg1Kb3C\n\tpotzWkXc1xmPzcQ1fvQMOfMwdS+4SNw4rY9f07Xb2K99rjMwZVDgESKIzhsDB5GY465sCsiQ\n\tcSAZRxqE49RTBq2+EQsbrQpIc8XiffAB8qexh5/QPzCmR4kJgCGeHIXBtgRj+nIkCJPZvZtf\n\tKr2EAbc6tgg6DkAEHJb+1okosV09+0+TXywYvtEop/WUOWQ+zo+Y/OBd+8Ptgt1pDRyOBzL8\n\tRXa8ZqRf0Mwg75D+dKntZeJHzPRJyrlfQokngAAs4PaFt6UfS+ypMAF37T6CeDArQC41V3ko\n\tlPn1yMsVD0p+6i3DPvA/GPIksDC4owjnzVX9kM8Zc5Cx+XoAN0w5Eqo4t6qEVbuettxx55gq\n\t8K8FieAjgjMSxngo/HST8TpFeqI5nVeq0/lqtBRQKumuIqDg+Bkr4L1V/PSB6XgQcOdhtd36\n\tOe9X9dXB8YSNt7VjOcO7BTmFn/Z8r92mSAfHXpb07YJWJosQOQARAQABtDBLaWVyYW4gQmlu\n\tZ2hhbSA8a2llcmFuLmJpbmdoYW1AaWRlYXNvbmJvYXJkLmNvbT6JAkAEEwEKACoCGwMFCwkI\n\tBwIGFQgJCgsCBBYCAwECHgECF4ACGQEFAlnDk/gFCQeA/YsACgkQoR5GchCkYf3X5w/9EaZ7\n\tcnUcT6dxjxrcmmMnfFPoQA1iQXr/MXQJBjFWfxRUWYzjvUJb2D/FpA8FY7y+vksoJP7pWDL7\n\tQTbksdwzagUEk7CU45iLWL/CZ/knYhj1I/+5LSLFmvZ/5Gf5xn2ZCsmg7C0MdW/GbJ8IjWA8\n\t/LKJSEYH8tefoiG6+9xSNp1p0Gesu3vhje/GdGX4wDsfAxx1rIYDYVoX4bDM+uBUQh7sQox/\n\tR1bS0AaVJzPNcjeC14MS226mQRUaUPc9250aj44WmDfcg44/kMsoLFEmQo2II9aOlxUDJ+x1\n\txohGbh9mgBoVawMO3RMBihcEjo/8ytW6v7xSF+xP4Oc+HOn7qebAkxhSWcRxQVaQYw3S9iZz\n\t2iA09AXAkbvPKuMSXi4uau5daXStfBnmOfalG0j+9Y6hOFjz5j0XzaoF6Pln0jisDtWltYhP\n\tX9LjFVhhLkTzPZB/xOeWGmsG4gv2V2ExbU3uAmb7t1VSD9+IO3Km4FtnYOKBWlxwEd8qOFpS\n\tjEqMXURKOiJvnw3OXe9MqG19XdeENA1KyhK5rqjpwdvPGfSn2V+SlsdJA0DFsobUScD9qXQw\n\tOvhapHe3XboK2+Rd7L+g/9Ud7ZKLQHAsMBXOVJbufA1AT+IaOt0ugMcFkAR5UbBg5+dZUYJj\n\t1QbPQcGmM3wfvuaWV5+SlJ+WeKIb8ta5Ag0EVgT9ZgEQAM4o5G/kmruIQJ3K9SYzmPishRHV\n\tDcUcvoakyXSX2mIoccmo9BHtD9MxIt+QmxOpYFNFM7YofX4lG0ld8H7FqoNVLd/+a0yru5Cx\n\tadeZBe3qr1eLns10Q90LuMo7/6zJhCW2w+HE7xgmCHejAwuNe3+7yt4QmwlSGUqdxl8cgtS1\n\tPlEK93xXDsgsJj/bw1EfSVdAUqhx8UQ3aVFxNug5OpoX9FdWJLKROUrfNeBE16RLrNrq2ROc\n\tiSFETpVjyC/oZtzRFnwD9Or7EFMi76/xrWzk+/b15RJ9WrpXGMrttHUUcYZEOoiC2lEXMSAF\n\tSSSj4vHbKDJ0vKQdEFtdgB1roqzxdIOg4rlHz5qwOTynueiBpaZI3PHDudZSMR5Fk6QjFooE\n\tXTw3sSl/km/lvUFiv9CYyHOLdygWohvDuMkV/Jpdkfq8XwFSjOle+vT/4VqERnYFDIGBxaRx\n\tkoBLfNDiiuR3lD8tnJ4A1F88K6ojOUs+jndKsOaQpDZV6iNFv8IaNIklTPvPkZsmNDhJMRHH\n\tIu60S7BpzNeQeT4yyY4dX9lC2JL/LOEpw8DGf5BNOP1KgjCvyp1/KcFxDAo89IeqljaRsCdP\n\t7WCIECWYem6pLwaw6IAL7oX+tEqIMPph/G/jwZcdS6Hkyt/esHPuHNwX4guqTbVEuRqbDzDI\n\t2DJO5FbxABEBAAGJAiUEGAEKAA8CGwwFAlnDlGsFCQeA/gIACgkQoR5GchCkYf1yYRAAq+Yo\n\tnbf9DGdK1kTAm2RTFg+w9oOp2Xjqfhds2PAhFFvrHQg1XfQR/UF/SjeUmaOmLSczM0s6XMeO\n\tVcE77UFtJ/+hLo4PRFKm5X1Pcar6g5m4xGqa+Xfzi9tRkwC29KMCoQOag1BhHChgqYaUH3yo\n\tUzaPwT/fY75iVI+yD0ih/e6j8qYvP8pvGwMQfrmN9YB0zB39YzCSdaUaNrWGD3iCBxg6lwSO\n\tLKeRhxxfiXCIYEf3vwOsP3YMx2JkD5doseXmWBGW1U0T/oJF+DVfKB6mv5UfsTzpVhJRgee7\n\t4jkjqFq4qsUGxcvF2xtRkfHFpZDbRgRlVmiWkqDkT4qMA+4q1y/dWwshSKi/uwVZNycuLsz+\n\t+OD8xPNCsMTqeUkAKfbD8xW4LCay3r/dD2ckoxRxtMD9eOAyu5wYzo/ydIPTh1QEj9SYyvp8\n\tO0g6CpxEwyHUQtF5oh15O018z3ZLztFJKR3RD42VKVsrnNDKnoY0f4U0z7eJv2NeF8xHMuiU\n\tRCIzqxX1GVYaNkKTnb/Qja8hnYnkUzY1Lc+OtwiGmXTwYsPZjjAaDX35J/RSKAoy5wGo/YFA\n\tJxB1gWThL4kOTbsqqXj9GLcyOImkW0lJGGR3o/fV91Zh63S5TKnf2YGGGzxki+ADdxVQAm+Q\n\tsbsRB8KNNvVXBOVNwko86rQqF9drZuw=","Organization":"Ideas on Board","Message-ID":"","Date":"Wed, 13 Feb 2019 16:30:36 +0000","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101\n\tThunderbird/60.4.0","MIME-Version":"1.0","In-Reply-To":"<20190213154153.GF5332@pendragon.ideasonboard.com>","Content-Type":"text/plain; charset=utf-8","Content-Language":"en-GB","Content-Transfer-Encoding":"8bit","Subject":"Re: [libcamera-devel] [PATCH v2 3/8] libcamera: v4l2_device:\n\tstreamOff() when releasing buffers","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.23","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Wed, 13 Feb 2019 16:30:39 -0000"}},{"id":820,"web_url":"https://patchwork.libcamera.org/comment/820/","msgid":"<20190213164828.GM5332@pendragon.ideasonboard.com>","date":"2019-02-13T16:48:28","subject":"Re: [libcamera-devel] [PATCH v2 3/8] libcamera: v4l2_device:\n\tstreamOff() when releasing buffers","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"On Wed, Feb 13, 2019 at 04:30:36PM +0000, Kieran Bingham wrote:\n> Hi Laurent,\n> \n> On 13/02/2019 15:41, Laurent Pinchart wrote:\n> > Hi Kieran,\n> > \n> > Thank you for the patch.\n> > \n> > On Wed, Feb 13, 2019 at 03:10:22PM +0000, Kieran Bingham wrote:\n> >> We must ensure that the stream is disabled before releasing buffers. It will\n> >> not hurt to call streamOff() even if it is already off before releasing any\n> >> buffers back to the device.\n> > \n> > I'm not sure about this one. Doesn't it indicate a problem in the caller\n> > instead ?\n> \n> Perhaps. It means (in the cases that I've hit) that the error paths have\n> not called streamOff().\n> \n> Is it more preferable to leave buffers 'un-released'?\n\nI think that would be better than trying to hide the issue, yes.\n\n> Perhaps would you prefer to see releaseBuffers return an error if it\n> fails?\n\nSounds good to me, with an error message logged.\n\n> As this is likely to be on cleanup paths, and destruction - what\n> would you expect the application to do in the event of failure to\n> releaseBuffers? (I guess - fix their code...)\n\nYes, fix their code :-) Buffers can also be released at runtime when\nswitching resolutions, in which case proper cleanup is mandatory, and\nerrors in the code flow should be logged instead of hidden.\n\n> Either way - I'll just drop this patch for now.\n> \n> >> Signed-off-by: Kieran Bingham \n> >> ---\n> >> src/libcamera/v4l2_device.cpp | 2 ++\n> >> 1 file changed, 2 insertions(+)\n> >>\n> >> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp\n> >> index 23c0da295905..83073c28b817 100644\n> >> --- a/src/libcamera/v4l2_device.cpp\n> >> +++ b/src/libcamera/v4l2_device.cpp\n> >> @@ -642,6 +642,8 @@ int V4L2Device::releaseBuffers()\n> >> {\n> >> \tLOG(V4L2, Debug) << \"Releasing bufferPool\";\n> >> \n> >> +\tstreamOff();\n> >> +\n> >> \trequestBuffers(0);\n> >> \tbufferPool_ = nullptr;\n> >>","headers":{"Return-Path":"","Received":["from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id ADEDC610AE\n\tfor ;\n\tWed, 13 Feb 2019 17:48:32 +0100 (CET)","from pendragon.ideasonboard.com\n\t(dfj612yhrgyx302h3jwwy-3.rev.dnainternet.fi\n\t[IPv6:2001:14ba:21f5:5b00:ce28:277f:58d7:3ca4])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 20F5F85;\n\tWed, 13 Feb 2019 17:48:32 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1550076512;\n\tbh=kzJ/k8PQjSJbjU8hhnHocLOx/0nDRemaYTclwrrp1nE=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=or3722fOdBbSoY/eeUAyx7ElgbuEN0vS0VRMhoGsbLO+vgX6LIdTP1R+/V0NfTxJf\n\tJEnrfwfGNNgK7/l/jxL6BpU869orCdU5b3xXl/jGSsJkGXvmb4YG3InG2kDrYjnqGe\n\t1/PCNpV4ttQOwCrvBIfg3Hah6gwKtFTvfGx7NcdE=","Date":"Wed, 13 Feb 2019 18:48:28 +0200","From":"Laurent Pinchart ","To":"Kieran Bingham ","Cc":"LibCamera Devel ","Message-ID":"<20190213164828.GM5332@pendragon.ideasonboard.com>","References":"<20190213151027.6376-1-kieran.bingham@ideasonboard.com>\n\t<20190213151027.6376-4-kieran.bingham@ideasonboard.com>\n\t<20190213154153.GF5332@pendragon.ideasonboard.com>\n\t","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"","User-Agent":"Mutt/1.10.1 (2018-07-13)","Subject":"Re: [libcamera-devel] [PATCH v2 3/8] libcamera: v4l2_device:\n\tstreamOff() when releasing buffers","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.23","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Wed, 13 Feb 2019 16:48:32 -0000"}}]