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{ "id": 1173, "url": "https://patchwork.libcamera.org/api/patches/1173/?format=api", "web_url": "https://patchwork.libcamera.org/patch/1173/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20190508151831.12274-9-niklas.soderlund@ragnatech.se>", "date": "2019-05-08T15:18:28", "name": "[libcamera-devel,v2,08/11] libcamera: media_device: Add functions to lock device for other processes", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": false, "hash": "20f71d574889c6692d0f6907d68c816410daf49a", "submitter": { "id": 5, "url": "https://patchwork.libcamera.org/api/people/5/?format=api", "name": "Niklas Söderlund", "email": "niklas.soderlund@ragnatech.se" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/1173/mbox/", "series": [ { "id": 300, "url": "https://patchwork.libcamera.org/api/series/300/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=300", "date": "2019-05-08T15:18:20", "name": "libcamerea: Add support for exclusive access to cameras between processes", "version": 2, "mbox": "https://patchwork.libcamera.org/series/300/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/1173/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/1173/checks/", "tags": {}, "headers": { "Return-Path": "<niklas.soderlund@ragnatech.se>", "Received": [ "from bin-mail-out-05.binero.net (bin-mail-out-05.binero.net\n\t[195.74.38.228])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id CED7860E6E\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tWed, 8 May 2019 17:18:55 +0200 (CEST)", "from localhost.localdomain (unknown [79.138.136.66])\n\tby bin-vsp-out-01.atm.binero.net (Halon) with ESMTPA\n\tid 973ecdad-71a4-11e9-8fa2-005056917a89;\n\tWed, 08 May 2019 17:18:54 +0200 (CEST)" ], "X-Halon-ID": "973ecdad-71a4-11e9-8fa2-005056917a89", "Authorized-sender": "niklas@soderlund.pp.se", "From": "=?utf-8?q?Niklas_S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>", "To": "libcamera-devel@lists.libcamera.org", "Date": "Wed, 8 May 2019 17:18:28 +0200", "Message-Id": "<20190508151831.12274-9-niklas.soderlund@ragnatech.se>", "X-Mailer": "git-send-email 2.21.0", "In-Reply-To": "<20190508151831.12274-1-niklas.soderlund@ragnatech.se>", "References": "<20190508151831.12274-1-niklas.soderlund@ragnatech.se>", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=UTF-8", "Content-Transfer-Encoding": "8bit", "Subject": "[libcamera-devel] [PATCH v2 08/11] libcamera: media_device: Add\n\tfunctions to lock device for other processes", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.23", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "X-List-Received-Date": "Wed, 08 May 2019 15:18:56 -0000" }, "content": "Add lock() and unlock() which are backed by lockf() and allows an\ninstance of libcamera to claim exclusive access to a media device.\nThese functions are the base of allowing multiple user of libcamera to\ncoexist in the system without stepping on each others toes.\n\nSigned-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>\n---\n src/libcamera/include/media_device.h | 4 ++\n src/libcamera/media_device.cpp | 58 +++++++++++++++++++++++++++-\n 2 files changed, 61 insertions(+), 1 deletion(-)", "diff": "diff --git a/src/libcamera/include/media_device.h b/src/libcamera/include/media_device.h\nindex e513a2fee1b91a1b..7b88e2875d59dfc3 100644\n--- a/src/libcamera/include/media_device.h\n+++ b/src/libcamera/include/media_device.h\n@@ -30,6 +30,9 @@ public:\n \tvoid release();\n \tbool busy() const { return acquired_; }\n \n+\tbool lock();\n+\tvoid unlock();\n+\n \tint populate();\n \tbool valid() const { return valid_; }\n \n@@ -58,6 +61,7 @@ private:\n \tint fd_;\n \tbool valid_;\n \tbool acquired_;\n+\tbool lockOwner_;\n \n \tint open();\n \tvoid close();\ndiff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp\nindex cd6a01ed452073e2..89b670348a63fd6b 100644\n--- a/src/libcamera/media_device.cpp\n+++ b/src/libcamera/media_device.cpp\n@@ -63,7 +63,8 @@ LOG_DEFINE_CATEGORY(MediaDevice)\n * populate() before the media graph can be queried.\n */\n MediaDevice::MediaDevice(const std::string &deviceNode)\n-\t: deviceNode_(deviceNode), fd_(-1), valid_(false), acquired_(false)\n+\t: deviceNode_(deviceNode), fd_(-1), valid_(false), acquired_(false),\n+\t lockOwner_(false)\n {\n }\n \n@@ -118,6 +119,61 @@ void MediaDevice::release()\n \tacquired_ = false;\n }\n \n+/**\n+ * \\brief Lock the device for use by other instances of libcamera\n+ *\n+ * Multiple instances of libcamera might be running on the same system, at the\n+ * same time. To allow the different instances to coexist, system resources in\n+ * the form of media devices must be accessible for enumerating the cameras\n+ * they provide at all times, while still allowing an instance to lock a\n+ * resource while it prepares to actively use a camera from the resource.\n+ *\n+ * This method shall not be called from a pipeline handler implementation\n+ * directly, as the base PipelineHandler implementation handles this on the\n+ * behalf of the specified implementation.\n+ *\n+ * \\return True if the device could be locked, false otherwise\n+ * \\sa unlock()\n+ */\n+bool MediaDevice::lock()\n+{\n+\tif (fd_ == -1)\n+\t\treturn false;\n+\n+\t/* Do not allow nested locking in the same libcamera instance. */\n+\tif (lockOwner_)\n+\t\treturn false;\n+\n+\tif (lockf(fd_, F_TLOCK, 0))\n+\t\treturn false;\n+\n+\tlockOwner_ = true;\n+\n+\treturn true;\n+}\n+\n+/**\n+ * \\brief Unlock the device and free it for use for libcamera instances\n+ *\n+ * This method shall not be called from a pipeline handler implementation\n+ * directly, as the base PipelineHandler implementation handles this on the\n+ * behalf of the specified implementation.\n+ *\n+ * \\sa lock()\n+ */\n+void MediaDevice::unlock()\n+{\n+\tif (fd_ == -1)\n+\t\treturn;\n+\n+\tif (!lockOwner_)\n+\t\treturn;\n+\n+\tlockOwner_ = false;\n+\n+\tlockf(fd_, F_ULOCK, 0);\n+}\n+\n /**\n * \\fn MediaDevice::busy()\n * \\brief Check if a device is in use\n", "prefixes": [ "libcamera-devel", "v2", "08/11" ] }