[{"id":14528,"web_url":"https://patchwork.libcamera.org/comment/14528/","msgid":"","date":"2021-01-11T17:09:04","subject":"Re: [libcamera-devel] [PATCH 1/2] libcamera: v4l2_videodevice:\n\tTrack streaming state","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Hi Umang,\n\nOn 11/01/2021 16:33, Umang Jain wrote:\n> From: Kieran Bingham \n> \n> Track the state of streamon/streamoff calls to simplify error paths.\n> \n> Ensuring that streamOff() can be called on non-streaming streams\n> facilitates simpler error code paths, where a set of devices can all\n> call streamOff regardless of their initialisation state.\n> \n> Signed-off-by: Kieran Bingham \n> Signed-off-by: Umang Jain \n\nThanks for re-vitalising this patch, I thought it wasn't useful back\nthen, so it's nice to see it re-surface and has become useful again.\n\n\n> ---\n> include/libcamera/internal/v4l2_videodevice.h | 2 ++\n> src/libcamera/v4l2_videodevice.cpp | 9 ++++++++-\n> 2 files changed, 10 insertions(+), 1 deletion(-)\n> \n> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h\n> index 529ca0e3..626dfbcd 100644\n> --- a/include/libcamera/internal/v4l2_videodevice.h\n> +++ b/include/libcamera/internal/v4l2_videodevice.h\n> @@ -249,6 +249,8 @@ private:\n> \tstd::map queuedBuffers_;\n> \n> \tEventNotifier *fdBufferNotifier_;\n> +\n> +\tbool streaming_;\n> };\n> \n> class V4L2M2MDevice\n> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp\n> index baf683d6..164954f2 100644\n> --- a/src/libcamera/v4l2_videodevice.cpp\n> +++ b/src/libcamera/v4l2_videodevice.cpp\n> @@ -481,7 +481,8 @@ const std::string V4L2DeviceFormat::toString() const\n> * \\param[in] deviceNode The file-system path to the video device node\n> */\n> V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)\n> -\t: V4L2Device(deviceNode), cache_(nullptr), fdBufferNotifier_(nullptr)\n> +\t: V4L2Device(deviceNode), cache_(nullptr), fdBufferNotifier_(nullptr),\n> +\t streaming_(false)\n> {\n> \t/*\n> \t * We default to an MMAP based CAPTURE video device, however this will\n> @@ -1554,6 +1555,8 @@ int V4L2VideoDevice::streamOn()\n> \t\treturn ret;\n> \t}\n> \n> +\tstreaming_ = true;\n> +\n> \treturn 0;\n> }\n> \n> @@ -1571,6 +1574,9 @@ int V4L2VideoDevice::streamOff()\n> {\n> \tint ret;\n> \n> +\tif (!streaming_ && queuedBuffers_.empty())\n> +\t\treturn 0;\n> +\n\nah nice, I was worried that we were going to be modifying streaming_\nwhen queuing buffers ... so that looks much nicer and doesn't detract\nfrom the meaning of streaming_\n\nSo Reviewed-by: Kieran Bingham \n\nBoth Niklas and Laurent had reviewed the earlier incantation of this\npatch, but it has now changed with this line so I'll let them decide if\nthey want to re-give tags.\n\nBut Laurent's previous comment regarding documentation update still holds:\n\n> I forgot to mention that previously, I think the documentation should be\n> updated to state that stopping an already stopped device is a no-op.\n\n\n--\nKieran\n\n\n\n\n> \tret = ioctl(VIDIOC_STREAMOFF, &bufferType_);\n> \tif (ret < 0) {\n> \t\tLOG(V4L2, Error)\n> @@ -1588,6 +1594,7 @@ int V4L2VideoDevice::streamOff()\n> \n> \tqueuedBuffers_.clear();\n> \tfdBufferNotifier_->setEnabled(false);\n> +\tstreaming_ = false;\n> \n> \treturn 0;\n> }\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 9BD5FBD808\n\tfor ;\n\tMon, 11 Jan 2021 17:09:08 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 20D3E680BE;\n\tMon, 11 Jan 2021 18:09:08 +0100 (CET)","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 6A5EE6010E\n\tfor ;\n\tMon, 11 Jan 2021 18:09:07 +0100 (CET)","from [192.168.0.20]\n\t(cpc89244-aztw30-2-0-cust3082.18-1.cable.virginm.net [86.31.172.11])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id E5E5F3E;\n\tMon, 11 Jan 2021 18:09:06 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"qrVoMmNp\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1610384947;\n\tbh=6uFtgAgIa/WHhxEEiIWV8LtRLIG4u42s5zvpJTNtVoQ=;\n\th=Reply-To:Subject:To:References:From:Date:In-Reply-To:From;\n\tb=qrVoMmNp0q4ZrkVqzAQnW8dQWbrUSSXgBwFduMNv9jeQIMTdRbRDYMlzpU3tecn3g\n\tAThhKNaYyYRvx61308p9r0fDnMnpnCbu36Dq7uVj7vtSFqYUVnSa3ekP9Vp4U6k5bq\n\tmTaDAwTx5D0H9PN1mFrpH43wZ+ukyDGPt27ThpsY=","To":"Umang Jain , libcamera-devel@lists.libcamera.org","References":"<20210111163359.43637-1-email@uajain.com>\n\t<20210111163359.43637-2-email@uajain.com>","From":"Kieran Bingham ","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\tZ2hhbSA8a2llcmFuLmJpbmdoYW1AaWRlYXNvbmJvYXJkLmNvbT6JAlcEEwEKAEECGwMFCwkI\n\tBwIGFQgJCgsCBBYCAwECHgECF4ACGQEWIQSQLdeYP70o/eNy1HqhHkZyEKRh/QUCXWTtygUJ\n\tCyJXZAAKCRChHkZyEKRh/f8dEACTDsbLN2nioNZMwyLuQRUAFcXNolDX48xcUXsWS2QjxaPm\n\tVsJx8Uy8aYkS85mdPBh0C83OovQR/OVbr8AxhGvYqBs3nQvbWuTl/+4od7DfK2VZOoKBAu5S\n\tQK2FYuUcikDqYcFWJ8DQnubxfE8dvzojHEkXw0sA4igINHDDFX3HJGZtLio+WpEFQtCbfTAG\n\tYZslasz1YZRbwEdSsmO3/kqy5eMnczlm8a21A3fKUo3g8oAZEFM+f4DUNzqIltg31OAB/kZS\n\tenKZQ/SWC8PmLg/ZXBrReYakxXtkP6w3FwMlzOlhGxqhIRNiAJfXJBaRhuUWzPOpEDE9q5YJ\n\tBmqQL2WJm1VSNNVxbXJHpaWMH1sA2R00vmvRrPXGwyIO0IPYeUYQa3gsy6k+En/aMQJd27dp\n\taScf9am9PFICPY5T4ppneeJLif2lyLojo0mcHOV+uyrds9XkLpp14GfTkeKPdPMrLLTsHRfH\n\tfA4I4OBpRrEPiGIZB/0im98MkGY/Mu6qxeZmYLCcgD6qz4idOvfgVOrNh+aA8HzIVR+RMW8H\n\tQGBN9f0E3kfwxuhl3omo6V7lDw8XOdmuWZNC9zPq1UfryVHANYbLGz9KJ4Aw6M+OgBC2JpkD\n\thXMdHUkC+d20dwXrwHTlrJi1YNp6rBc+xald3wsUPOZ5z8moTHUX/uPA/qhGsbkCDQRWBP1m\n\tARAAzijkb+Sau4hAncr1JjOY+KyFEdUNxRy+hqTJdJfaYihxyaj0Ee0P0zEi35CbE6lgU0Uz\n\ttih9fiUbSV3wfsWqg1Ut3/5rTKu7kLFp15kF7eqvV4uezXRD3Qu4yjv/rMmEJbbD4cTvGCYI\n\td6MDC417f7vK3hCbCVIZSp3GXxyC1LU+UQr3fFcOyCwmP9vDUR9JV0BSqHHxRDdpUXE26Dk6\n\tmhf0V1YkspE5St814ETXpEus2urZE5yJIUROlWPIL+hm3NEWfAP06vsQUyLvr/GtbOT79vXl\n\tEn1aulcYyu20dRRxhkQ6iILaURcxIAVJJKPi8dsoMnS8pB0QW12AHWuirPF0g6DiuUfPmrA5\n\tPKe56IGlpkjc8cO51lIxHkWTpCMWigRdPDexKX+Sb+W9QWK/0JjIc4t3KBaiG8O4yRX8ml2R\n\t+rxfAVKM6V769P/hWoRGdgUMgYHFpHGSgEt80OKK5HeUPy2cngDUXzwrqiM5Sz6Od0qw5pCk\n\tNlXqI0W/who0iSVM+8+RmyY0OEkxEcci7rRLsGnM15B5PjLJjh1f2ULYkv8s4SnDwMZ/kE04\n\t/UqCMK/KnX8pwXEMCjz0h6qWNpGwJ0/tYIgQJZh6bqkvBrDogAvuhf60Sogw+mH8b+PBlx1L\n\toeTK396wc+4c3BfiC6pNtUS5GpsPMMjYMk7kVvEAEQEAAYkCPAQYAQoAJgIbDBYhBJAt15g/\n\tvSj943LUeqEeRnIQpGH9BQJdizzIBQkLSKZiAAoJEKEeRnIQpGH9eYgQAJpjaWNgqNOnMTmD\n\tMJggbwjIotypzIXfhHNCeTkG7+qCDlSaBPclcPGYrTwCt0YWPU2TgGgJrVhYT20ierN8LUvj\n\t6qOPTd+Uk7NFzL65qkh80ZKNBFddx1AabQpSVQKbdcLb8OFs85kuSvFdgqZwgxA1vl4TFhNz\n\tPZ79NAmXLackAx3sOVFhk4WQaKRshCB7cSl+RIng5S/ThOBlwNlcKG7j7W2MC06BlTbdEkUp\n\tECzuuRBv8wX4OQl+hbWbB/VKIx5HKlLu1eypen/5lNVzSqMMIYkkZcjV2SWQyUGxSwq0O/sx\n\tS0A8/atCHUXOboUsn54qdxrVDaK+6jIAuo8JiRWctP16KjzUM7MO0/+4zllM8EY57rXrj48j\n\tsbEYX0YQnzaj+jO6kJtoZsIaYR7rMMq9aUAjyiaEZpmP1qF/2sYenDx0Fg2BSlLvLvXM0vU8\n\tpQk3kgDu7kb/7PRYrZvBsr21EIQoIjXbZxDz/o7z95frkP71EaICttZ6k9q5oxxA5WC6sTXc\n\tMW8zs8avFNuA9VpXt0YupJd2ijtZy2mpZNG02fFVXhIn4G807G7+9mhuC4XG5rKlBBUXTvPU\n\tAfYnB4JBDLmLzBFavQfvonSfbitgXwCG3vS+9HEwAjU30Bar1PEOmIbiAoMzuKeRm2LVpmq4\n\tWZw01QYHU/GUV/zHJSFk","Organization":"Ideas on Board","Message-ID":"","Date":"Mon, 11 Jan 2021 17:09:04 +0000","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101\n\tThunderbird/68.10.0","MIME-Version":"1.0","In-Reply-To":"<20210111163359.43637-2-email@uajain.com>","Content-Language":"en-GB","Subject":"Re: [libcamera-devel] [PATCH 1/2] libcamera: v4l2_videodevice:\n\tTrack streaming state","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Reply-To":"kieran.bingham@ideasonboard.com","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]