[{"id":4838,"web_url":"https://patchwork.libcamera.org/comment/4838/","msgid":"<55667015-e16c-d19e-17e2-2b8b7df153d6@ideasonboard.com>","date":"2020-05-18T13:20:54","subject":"Re: [libcamera-devel] [PATCH v2 2/5] libcamera: device_enumerator:\n\tEmit a signal when a new device is hotplugged","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Hi Umang,\n\nOn 13/05/2020 18:29, Umang Jain wrote:\n> Emit a signal whenever is a new MediaDevice is added to the\n\ns/ whenever is a / whenever a /\n\n> DeviceEnumerator. This will allow CameraManager to get notified\n\ns/get/be/\n\n> about the new devices that have been hot-plugged.\n> \n> Signed-off-by: Umang Jain \n> ---\n> src/libcamera/camera_manager.cpp | 4 ++--\n> src/libcamera/device_enumerator.cpp | 12 ++++++++++++\n> src/libcamera/include/device_enumerator.h | 4 ++++\n> 3 files changed, 18 insertions(+), 2 deletions(-)\n> \n> diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp\n> index 1579ad4..a13cfe1 100644\n> --- a/src/libcamera/camera_manager.cpp\n> +++ b/src/libcamera/camera_manager.cpp\n> @@ -154,12 +154,12 @@ void CameraManager::Private::enumerateDevices()\n> \t\t}\n> \t}\n> \n> -\t/* \\todo register hot-plug callback here */\n> +\tenumerator_->newDevicesFound.connect(this, &Private::enumerateDevices);\n\nI'm half tempted to suggest calling this signal hotplug ...\n\nBut I think it's just bikesheding as then I end up down the path of\nshould it be hotPlug or hotplug, and should we have hotUnPlug or\nhotplugRemove or ... oh it's a rabbit hole ;-)\n\n\n> }\n> \n> void CameraManager::Private::cleanup()\n> {\n> -\t/* \\todo unregister hot-plug callback here */\n> +\tenumerator_->newDevicesFound.disconnect(this, &Private::enumerateDevices);\n> \n> \t/*\n> \t * Release all references to cameras and pipeline handlers to ensure\n> diff --git a/src/libcamera/device_enumerator.cpp b/src/libcamera/device_enumerator.cpp\n> index dd17e3e..0492a86 100644\n> --- a/src/libcamera/device_enumerator.cpp\n> +++ b/src/libcamera/device_enumerator.cpp\n> @@ -227,6 +227,15 @@ std::unique_ptr DeviceEnumerator::createDevice(const std::string &d\n> \treturn media;\n> }\n> \n> +/**\n\nI think this is missing tieing it to the signal?\n\nNot 100% sure how to do that with doxygen, perhaps it's just\n\n \\var newDevicesFound\n\nPresumably other signals are documented to show how this is done.\n\n\n> +* \\brief Notify of new media devices being found\n> +*\n> +* This signal is emitted when the device enumerator finds new media devices in\n> +* the system. It may be emitted for every newly detected device, or once for\n> +* multiple of devices, at the discretion of the device enumerator. Not all\n> +* device enumerator types may support dynamic detection of new devices.\n> +*/\n> +\n> /**\n> * \\brief Add a media device to the enumerator\n> * \\param[in] media media device instance to add\n> @@ -242,6 +251,9 @@ void DeviceEnumerator::addDevice(std::unique_ptr &&media)\n> \t\t<< \"Added device \" << media->deviceNode() << \": \" << media->driver();\n> \n> \tdevices_.push_back(std::move(media));\n> +\n> +\t/* \\todo: To batch multiple additions, emit with a small delay here. */\n\nDo we have support already to register a timeout or such to make this\ncall N milliseconds after the last registration of a device?\n\nSounds like a good way to reduce the signal frequency...\n\n> +\tnewDevicesFound.emit();\n> }\n> \n> /**\n> diff --git a/src/libcamera/include/device_enumerator.h b/src/libcamera/include/device_enumerator.h\n> index 433e357..cd4e846 100644\n> --- a/src/libcamera/include/device_enumerator.h\n> +++ b/src/libcamera/include/device_enumerator.h\n> @@ -13,6 +13,8 @@\n> \n> #include \n> \n> +#include \n> +\n> namespace libcamera {\n> \n> class MediaDevice;\n> @@ -43,6 +45,8 @@ public:\n> \n> \tstd::shared_ptr search(const DeviceMatch &dm);\n> \n> +\tSignal<> newDevicesFound;\n> +\n> protected:\n> \tstd::unique_ptr createDevice(const std::string &deviceNode);\n> \tvoid addDevice(std::unique_ptr &&media);\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 755E8603DA\n\tfor ;\n\tMon, 18 May 2020 15:20:58 +0200 (CEST)","from [192.168.0.20]\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 92B01258;\n\tMon, 18 May 2020 15:20:57 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"PYaaPLZx\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1589808058;\n\tbh=DzPQxNzDbsF+4hGLVevYWaW25wnLLCE5xaq1K0GtazI=;\n\th=Reply-To:Subject:To:References:From:Date:In-Reply-To:From;\n\tb=PYaaPLZxnZzhaiyTeG+nKLIP6mne8Jn+awebdn6FyrALp304ZnLM9ck3k2pNqEpe+\n\tXeeiQERY8gxXxiUKLwsD2M7hLeIiWOJdpnMzXvRDB7Fr7cxiVfR1Ww+G7NitWqnaEf\n\te0sSkJHnpu/3pvWxfjze5xU9zRxr+8znIs+d1MBU=","Reply-To":"kieran.bingham@ideasonboard.com","To":"Umang Jain ,\n\tlibcamera-devel ","References":"<20200513172950.72685-1-email@uajain.com>\n\t<20200513172950.72685-3-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":"<55667015-e16c-d19e-17e2-2b8b7df153d6@ideasonboard.com>","Date":"Mon, 18 May 2020 14:20:54 +0100","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101\n\tThunderbird/68.7.0","MIME-Version":"1.0","In-Reply-To":"<20200513172950.72685-3-email@uajain.com>","Content-Type":"text/plain; charset=utf-8","Content-Language":"en-GB","Content-Transfer-Encoding":"8bit","Subject":"Re: [libcamera-devel] [PATCH v2 2/5] libcamera: device_enumerator:\n\tEmit a signal when a new device is hotplugged","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","X-List-Received-Date":"Mon, 18 May 2020 13:20:58 -0000"}}]