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{ "id": 3907, "url": "https://patchwork.libcamera.org/api/patches/3907/?format=api", "web_url": "https://patchwork.libcamera.org/patch/3907/", "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": "<20200603141609.18584-4-paul.elder@ideasonboard.com>", "date": "2020-06-03T14:16:07", "name": "[libcamera-devel,3/5] v4l2: v4l2_camera_proxy: Acquire only one buffer semaphore on VIDIOC_DQBUF", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": false, "hash": "bf3a9190cc82de317ede01104556989699e5d6c7", "submitter": { "id": 17, "url": "https://patchwork.libcamera.org/api/people/17/?format=api", "name": "Paul Elder", "email": "paul.elder@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/3907/mbox/", "series": [ { "id": 946, "url": "https://patchwork.libcamera.org/api/series/946/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=946", "date": "2020-06-03T14:16:04", "name": "Support qv4l2 with v4l2-compat", "version": 1, "mbox": "https://patchwork.libcamera.org/series/946/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/3907/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/3907/checks/", "tags": {}, "headers": { "Return-Path": "<paul.elder@ideasonboard.com>", "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 B988D6114D\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tWed, 3 Jun 2020 16:16:26 +0200 (CEST)", "from emerald.amanokami.net (fs76eef344.knge213.ap.nuro.jp\n\t[118.238.243.68])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 8FE5827C;\n\tWed, 3 Jun 2020 16:16:25 +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=\"rvA2fels\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1591193786;\n\tbh=0jvjRyLFjW1dQ/QuY+iycDWse4ctjcTQ5yW9YRmxhMY=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=rvA2felsjYH5KhBFV3+yP8g5F+dNeUzHatLLb0BNEQyeyfNS2ngmOA7uNsQZ3EWon\n\tti7KlIcORQJBCPhOlKmbYqWKqlwsJ93CKwEkN+zbbuPt3C5RpkdB93uHU6yN3jEa3L\n\t3xgtVaHGY/rkVGiXb/l5EZ8hVrH1QN+vPyybtR1Q=", "From": "Paul Elder <paul.elder@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Date": "Wed, 3 Jun 2020 23:16:07 +0900", "Message-Id": "<20200603141609.18584-4-paul.elder@ideasonboard.com>", "X-Mailer": "git-send-email 2.20.1", "In-Reply-To": "<20200603141609.18584-1-paul.elder@ideasonboard.com>", "References": "<20200603141609.18584-1-paul.elder@ideasonboard.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Subject": "[libcamera-devel] [PATCH 3/5] v4l2: v4l2_camera_proxy: Acquire only\n\tone buffer semaphore on VIDIOC_DQBUF", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "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, 03 Jun 2020 14:16:27 -0000" }, "content": "We use a semaphore to atomically keep track of how many buffers are\navailable for dequeueing. The check for how to acquire the semaphore was\nincorrect, leading to a double acquire upon a successful nonblocking\nacquire. Fix this.\n\nSigned-off-by: Paul Elder <paul.elder@ideasonboard.com>\n---\n src/v4l2/v4l2_camera_proxy.cpp | 2 +-\n 1 file changed, 1 insertion(+), 1 deletion(-)", "diff": "diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\nindex ec6d265d..d2419b96 100644\n--- a/src/v4l2/v4l2_camera_proxy.cpp\n+++ b/src/v4l2/v4l2_camera_proxy.cpp\n@@ -428,7 +428,7 @@ int V4L2CameraProxy::vidioc_dqbuf(struct v4l2_buffer *arg)\n \n \tif (nonBlocking_ && !vcam_->bufferSema_.tryAcquire())\n \t\treturn -EAGAIN;\n-\telse\n+\telse if (!nonBlocking_)\n \t\tvcam_->bufferSema_.acquire();\n \n \tupdateBuffers();\n", "prefixes": [ "libcamera-devel", "3/5" ] }