[{"id":5043,"web_url":"https://patchwork.libcamera.org/comment/5043/","msgid":"<20200605101659.GH5852@pendragon.ideasonboard.com>","date":"2020-06-05T10:16:59","subject":"Re: [libcamera-devel] [PATCH v2 6/7] v4l2: v4l2_compat: Add eventfd\n\tsignaling to support polling","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Paul,\n\nThank you for the patch.\n\nOn Fri, Jun 05, 2020 at 06:01:05PM +0900, Paul Elder wrote:\n> To support polling, we need to be able to signal when data is\n> available to be read (POLLIN), as well as events (POLLPRI). Add the\n> necessary calls to eventfd to allow signaling POLLIN. We signal POLLIN\n> by writing writing to the eventfd, and clear it by reading from the\n> eventfd, upon VIDIOC_DQBUF.\n> \n> Note that eventfd does not support signaling POLLPRI, so we don't yet\n> support V4L2 events.\n> \n> Signed-off-by: Paul Elder \n\nReviewed-by: Laurent Pinchart \n\n> ---\n> Changes in v2: use eventfd instead of socket\n> ---\n> src/v4l2/v4l2_camera.cpp | 9 +++++++++\n> src/v4l2/v4l2_camera.h | 3 +++\n> src/v4l2/v4l2_camera_proxy.cpp | 10 ++++++++++\n> src/v4l2/v4l2_camera_proxy.h | 4 ++++\n> src/v4l2/v4l2_compat_manager.cpp | 7 ++++++-\n> 5 files changed, 32 insertions(+), 1 deletion(-)\n> \n> diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp\n> index 4da01a45..3c369328 100644\n> --- a/src/v4l2/v4l2_camera.cpp\n> +++ b/src/v4l2/v4l2_camera.cpp\n> @@ -8,6 +8,7 @@\n> #include \"v4l2_camera.h\"\n> \n> #include \n> +#include \n> \n> #include \"libcamera/internal/log.h\"\n> \n> @@ -53,6 +54,11 @@ void V4L2Camera::close()\n> \tcamera_->release();\n> }\n> \n> +void V4L2Camera::bind(int efd)\n> +{\n> +\tefd_ = efd;\n> +}\n> +\n> void V4L2Camera::getStreamConfig(StreamConfiguration *streamConfig)\n> {\n> \t*streamConfig = config_->at(0);\n> @@ -84,6 +90,9 @@ void V4L2Camera::requestComplete(Request *request)\n> \tcompletedBuffers_.push_back(std::move(metadata));\n> \tbufferLock_.unlock();\n> \n> +\tuint64_t data = 1;\n> +\t::write(efd_, &data, sizeof(data));\n> +\n> \tbufferSema_.release();\n> }\n> \n> diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h\n> index 303eda44..33f5eb02 100644\n> --- a/src/v4l2/v4l2_camera.h\n> +++ b/src/v4l2/v4l2_camera.h\n> @@ -39,6 +39,7 @@ public:\n> \n> \tint open();\n> \tvoid close();\n> +\tvoid bind(int efd);\n> \tvoid getStreamConfig(StreamConfiguration *streamConfig);\n> \tstd::vector completedBuffers();\n> \n> @@ -70,6 +71,8 @@ private:\n> \n> \tstd::deque> pendingRequests_;\n> \tstd::deque> completedBuffers_;\n> +\n> +\tint efd_;\n> };\n> \n> #endif /* __V4L2_CAMERA_H__ */\n> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\n> index cbe9e026..7ee4c0cb 100644\n> --- a/src/v4l2/v4l2_camera_proxy.cpp\n> +++ b/src/v4l2/v4l2_camera_proxy.cpp\n> @@ -13,6 +13,7 @@\n> #include \n> #include \n> #include \n> +#include \n> \n> #include \n> #include \n> @@ -451,6 +452,9 @@ int V4L2CameraProxy::vidioc_dqbuf(struct v4l2_buffer *arg)\n> \n> \tcurrentBuf_ = (currentBuf_ + 1) % bufferCount_;\n> \n> +\tuint64_t data;\n> +\t::read(efd_, &data, sizeof(data));\n> +\n> \treturn 0;\n> }\n> \n> @@ -529,6 +533,12 @@ int V4L2CameraProxy::ioctl(unsigned long request, void *arg)\n> \treturn ret;\n> }\n> \n> +void V4L2CameraProxy::bind(int fd)\n> +{\n> +\tefd_ = fd;\n> +\tvcam_->bind(fd);\n> +}\n> +\n> struct PixelFormatPlaneInfo {\n> \tunsigned int bitsPerPixel;\n> \tunsigned int hSubSampling;\n> diff --git a/src/v4l2/v4l2_camera_proxy.h b/src/v4l2/v4l2_camera_proxy.h\n> index af9f9bbe..7c65c886 100644\n> --- a/src/v4l2/v4l2_camera_proxy.h\n> +++ b/src/v4l2/v4l2_camera_proxy.h\n> @@ -33,6 +33,8 @@ public:\n> \n> \tint ioctl(unsigned long request, void *arg);\n> \n> +\tvoid bind(int fd);\n> +\n> private:\n> \tbool validateBufferType(uint32_t type);\n> \tbool validateMemoryType(uint32_t memory);\n> @@ -77,6 +79,8 @@ private:\n> \tstd::map mmaps_;\n> \n> \tstd::unique_ptr vcam_;\n> +\n> +\tint efd_;\n> };\n> \n> #endif /* __V4L2_CAMERA_PROXY_H__ */\n> diff --git a/src/v4l2/v4l2_compat_manager.cpp b/src/v4l2/v4l2_compat_manager.cpp\n> index 2338a0ee..56533c4f 100644\n> --- a/src/v4l2/v4l2_compat_manager.cpp\n> +++ b/src/v4l2/v4l2_compat_manager.cpp\n> @@ -155,12 +155,17 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod\n> \tif (ret < 0)\n> \t\treturn ret;\n> \n> -\tint efd = eventfd(0, oflag & (O_CLOEXEC | O_NONBLOCK));\n> +\tint efd = eventfd(0, EFD_SEMAPHORE |\n> +\t\t\t ((oflag & O_CLOEXEC) ? EFD_CLOEXEC : 0) |\n> +\t\t\t ((oflag & O_NONBLOCK) ? EFD_NONBLOCK : 0));\n> \tif (efd < 0) {\n> +\t\tint err = errno;\n> \t\tproxy->close();\n> +\t\terrno = err;\n> \t\treturn efd;\n> \t}\n> \n> +\tproxy->bind(efd);\n> \tdevices_.emplace(efd, proxy);\n> \n> \treturn efd;","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 384A2603C9\n\tfor ;\n\tFri, 5 Jun 2020 12:17:19 +0200 (CEST)","from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi\n\t[81.175.216.236])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 661BC27C;\n\tFri, 5 Jun 2020 12:17:18 +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=\"Ghf/09Te\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1591352239;\n\tbh=F3t/67nyF7jC703Lohr0vho9G0hwGk5OMWqYU9KCRWY=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=Ghf/09Teg7qeO2KrOY41pW6qqZMvvPjj1UG8+tZ3Oo5PrJBpIvEsP9aftNGjSslDy\n\tWqK16TmCkS5bDW6ZkMdpbwIbEsoOcOajU8miXxBC8gsxx+xkBNA3LajfjQd1adelwB\n\tszKWguWY7r5IShMzpAzCeWbjUPjPvvnKEk55Q3Ts=","Date":"Fri, 5 Jun 2020 13:16:59 +0300","From":"Laurent Pinchart ","To":"Paul Elder ","Cc":"libcamera-devel@lists.libcamera.org","Message-ID":"<20200605101659.GH5852@pendragon.ideasonboard.com>","References":"<20200605090106.15424-1-paul.elder@ideasonboard.com>\n\t<20200605090106.15424-7-paul.elder@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20200605090106.15424-7-paul.elder@ideasonboard.com>","Subject":"Re: [libcamera-devel] [PATCH v2 6/7] v4l2: v4l2_compat: Add eventfd\n\tsignaling to support polling","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":"Fri, 05 Jun 2020 10:17:19 -0000"}},{"id":5141,"web_url":"https://patchwork.libcamera.org/comment/5141/","msgid":"<06e80b31-b1a1-93f6-5d21-63612aea842c@ideasonboard.com>","date":"2020-06-08T19:06:45","subject":"Re: [libcamera-devel] [PATCH v2 6/7] v4l2: v4l2_compat: Add eventfd\n\tsignaling to support polling","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Hi Paul,\n\nThis patch has introduced some warnings from coverity scan:\n\nOn 05/06/2020 10:01, Paul Elder wrote:\n> To support polling, we need to be able to signal when data is\n> available to be read (POLLIN), as well as events (POLLPRI). Add the\n> necessary calls to eventfd to allow signaling POLLIN. We signal POLLIN\n> by writing writing to the eventfd, and clear it by reading from the\n> eventfd, upon VIDIOC_DQBUF.\n> \n> Note that eventfd does not support signaling POLLPRI, so we don't yet\n> support V4L2 events.\n> \n> Signed-off-by: Paul Elder \n> \n> ---\n> Changes in v2: use eventfd instead of socket\n> ---\n> src/v4l2/v4l2_camera.cpp | 9 +++++++++\n> src/v4l2/v4l2_camera.h | 3 +++\n> src/v4l2/v4l2_camera_proxy.cpp | 10 ++++++++++\n> src/v4l2/v4l2_camera_proxy.h | 4 ++++\n> src/v4l2/v4l2_compat_manager.cpp | 7 ++++++-\n> 5 files changed, 32 insertions(+), 1 deletion(-)\n> \n> diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp\n> index 4da01a45..3c369328 100644\n> --- a/src/v4l2/v4l2_camera.cpp\n> +++ b/src/v4l2/v4l2_camera.cpp\n> @@ -8,6 +8,7 @@\n> #include \"v4l2_camera.h\"\n> \n> #include \n> +#include \n> \n> #include \"libcamera/internal/log.h\"\n> \n> @@ -53,6 +54,11 @@ void V4L2Camera::close()\n> \tcamera_->release();\n> }\n> \n> +void V4L2Camera::bind(int efd)\n> +{\n> +\tefd_ = efd;\n> +}\n> +\n> void V4L2Camera::getStreamConfig(StreamConfiguration *streamConfig)\n> {\n> \t*streamConfig = config_->at(0);\n> @@ -84,6 +90,9 @@ void V4L2Camera::requestComplete(Request *request)\n> \tcompletedBuffers_.push_back(std::move(metadata));\n> \tbufferLock_.unlock();\n> \n> +\tuint64_t data = 1;\n> +\t::write(efd_, &data, sizeof(data));\n\n** CID 290743: Error handling issues (CHECKED_RETURN)\n/home/linuxembedded/iob/libcamera/libcamera-daily/src/v4l2/v4l2_camera.cpp:\n94 in V4L2Camera::requestComplete(libcamera::Request *)()","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 073DA61027\n\tfor ;\n\tMon, 8 Jun 2020 21:06:49 +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 41BFF2C9;\n\tMon, 8 Jun 2020 21:06:48 +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=\"u3Ac1yVy\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1591643208;\n\tbh=LhhKVNDsA84N7r5/7EE/O85v4wLK9BEx5PvGzvaZEXc=;\n\th=Reply-To:Subject:To:References:From:Date:In-Reply-To:From;\n\tb=u3Ac1yVyHddICr2dvA59i6wDgFS15ARITaGhZlFLXCuZekniyNoVEakdq6zwJwwHi\n\t/a2pyLlu52QGjxH2rtjtLIgeNWWWrjpQETZ7YGhyRhPR0yCMTn7aOhij4efjynjPH4\n\tJi6oBIDty9ca79vw3nf7KvNH39Cn4hZDUcO66MNs=","Reply-To":"kieran.bingham@ideasonboard.com","To":"Paul Elder ,\n\tlibcamera-devel@lists.libcamera.org","References":"<20200605090106.15424-1-paul.elder@ideasonboard.com>\n\t<20200605090106.15424-7-paul.elder@ideasonboard.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":"<06e80b31-b1a1-93f6-5d21-63612aea842c@ideasonboard.com>","Date":"Mon, 8 Jun 2020 20:06:45 +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":"<20200605090106.15424-7-paul.elder@ideasonboard.com>","Content-Type":"text/plain; charset=utf-8","Content-Language":"en-GB","Content-Transfer-Encoding":"8bit","Subject":"Re: [libcamera-devel] [PATCH v2 6/7] v4l2: v4l2_compat: Add eventfd\n\tsignaling to support polling","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, 08 Jun 2020 19:06:49 -0000"}}]