{"id":2908,"url":"https://patchwork.libcamera.org/api/patches/2908/?format=json","web_url":"https://patchwork.libcamera.org/patch/2908/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20200227200407.490616-27-nicolas.dufresne@collabora.com>","date":"2020-02-27T20:04:06","name":"[libcamera-devel,v2,26/27] gst: libcamerasrc: Prevent src task deadlock on exhausted buffer pool","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"196f89753f9f2ea18f93b86c09e274ed0a730451","submitter":{"id":31,"url":"https://patchwork.libcamera.org/api/people/31/?format=json","name":"Nicolas Dufresne","email":"nicolas.dufresne@collabora.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/2908/mbox/","series":[{"id":693,"url":"https://patchwork.libcamera.org/api/series/693/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=693","date":"2020-02-27T20:03:40","name":"GStreamer Element for libcamera","version":2,"mbox":"https://patchwork.libcamera.org/series/693/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/2908/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/2908/checks/","tags":{},"headers":{"Return-Path":"","Received":["from bhuna.collabora.co.uk (bhuna.collabora.co.uk\n\t[IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 6F4EE62755\n\tfor ;\n\tThu, 27 Feb 2020 21:04:30 +0100 (CET)","from [127.0.0.1] (localhost [127.0.0.1])\n\t(Authenticated sender: nicolas) with ESMTPSA id D9C662949DF"],"From":"Nicolas Dufresne ","To":"libcamera-devel@lists.libcamera.org","Cc":"Jakub Adam ","Date":"Thu, 27 Feb 2020 15:04:06 -0500","Message-Id":"<20200227200407.490616-27-nicolas.dufresne@collabora.com>","X-Mailer":"git-send-email 2.24.1","In-Reply-To":"<20200227200407.490616-1-nicolas.dufresne@collabora.com>","References":"<20200227200407.490616-1-nicolas.dufresne@collabora.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v2 26/27] gst: libcamerasrc: Prevent src\n\ttask deadlock on exhausted buffer pool","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":"Thu, 27 Feb 2020 20:04:31 -0000"},"content":"From: Jakub Adam \n\nAllow GstLibcameraPool to notify the source when a new buffer has become\navailable in a previously exhausted buffer pool. This can be used to\nresume a src task that got paused because it couldn't acquire a buffer.\n\nWithout this change the src task will never resume from pause once the\npool gets exhausted.\n\nTo trigger the deadlock (it doesn't happen every time), run:\n\n gst-launch-1.0 libcamerasrc ! queue ! glimagesink\n\nSigned-off-by: Jakub Adam \n---\n src/gstreamer/gstlibcamerapool.cpp | 16 ++++++++++++++++\n src/gstreamer/gstlibcamerapool.h | 6 ++++++\n src/gstreamer/gstlibcamerasrc.cpp | 14 ++++++++++++--\n 3 files changed, 34 insertions(+), 2 deletions(-)","diff":"diff --git a/src/gstreamer/gstlibcamerapool.cpp b/src/gstreamer/gstlibcamerapool.cpp\nindex f85c3aa..5aa0eeb 100644\n--- a/src/gstreamer/gstlibcamerapool.cpp\n+++ b/src/gstreamer/gstlibcamerapool.cpp\n@@ -18,6 +18,8 @@ struct _GstLibcameraPool {\n \n \tGstAtomicQueue *queue;\n \tGstLibcameraAllocator *allocator;\n+\tGstLibcameraBufferNotify buffer_notify;\n+\tgpointer buffer_notify_data;\n \tStream *stream;\n };\n \n@@ -54,7 +56,12 @@ static void\n gst_libcamera_pool_release_buffer(GstBufferPool *pool, GstBuffer *buffer)\n {\n \tGstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);\n+\tbool do_notify = gst_atomic_queue_length(self->queue) == 0;\n+\n \tgst_atomic_queue_push(self->queue, buffer);\n+\n+\tif (do_notify && self->buffer_notify)\n+\t\tself->buffer_notify(self->buffer_notify_data);\n }\n \n static void\n@@ -108,6 +115,15 @@ gst_libcamera_pool_new(GstLibcameraAllocator *allocator, Stream *stream)\n \treturn pool;\n }\n \n+void\n+gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,\n+\t\t\t\t GstLibcameraBufferNotify notify,\n+\t\t\t\t gpointer data)\n+{\n+\tself->buffer_notify = notify;\n+\tself->buffer_notify_data = data;\n+}\n+\n Stream *\n gst_libcamera_pool_get_stream(GstLibcameraPool *self)\n {\ndiff --git a/src/gstreamer/gstlibcamerapool.h b/src/gstreamer/gstlibcamerapool.h\nindex 6fd2913..545be01 100644\n--- a/src/gstreamer/gstlibcamerapool.h\n+++ b/src/gstreamer/gstlibcamerapool.h\n@@ -20,9 +20,15 @@\n #define GST_TYPE_LIBCAMERA_POOL gst_libcamera_pool_get_type()\n G_DECLARE_FINAL_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_LIBCAMERA, POOL, GstBufferPool)\n \n+typedef void (*GstLibcameraBufferNotify)(gpointer data);\n+\n GstLibcameraPool *gst_libcamera_pool_new(GstLibcameraAllocator *allocator,\n \t\t\t\t\t libcamera::Stream *stream);\n \n+void gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,\n+\t\t\t\t\t GstLibcameraBufferNotify notify,\n+\t\t\t\t\t gpointer data);\n+\n libcamera::Stream *gst_libcamera_pool_get_stream(GstLibcameraPool *self);\n \n libcamera::Stream *gst_libcamera_buffer_get_stream(GstBuffer *buffer);\ndiff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp\nindex fe60584..ecbfe37 100644\n--- a/src/gstreamer/gstlibcamerasrc.cpp\n+++ b/src/gstreamer/gstlibcamerasrc.cpp\n@@ -434,6 +434,10 @@ gst_libcamera_src_task_enter(GstTask *task, GThread *thread, gpointer user_data)\n \t\tconst StreamConfiguration &stream_cfg = state->config->at(i);\n \t\tGstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator,\n \t\t\t\t\t\t\t\tstream_cfg.stream());\n+\t\tgst_libcamera_pool_set_buffer_notify(pool,\n+\t\t\t\t\t\t (GstLibcameraBufferNotify)gst_libcamera_resume_task,\n+\t\t\t\t\t\t task);\n+\n \t\tgst_libcamera_pad_set_pool(srcpad, pool);\n \t\tgst_flow_combiner_add_pad(self->flow_combiner, srcpad);\n \t}\n@@ -468,8 +472,14 @@ gst_libcamera_src_task_leave(GstTask *task, GThread *thread, gpointer user_data)\n \n \tstate->cam->stop();\n \n-\tfor (GstPad *srcpad : state->srcpads)\n-\t\tgst_libcamera_pad_set_pool(srcpad, NULL);\n+\tfor (GstPad *srcpad : state->srcpads) {\n+\t\tauto *pool = gst_libcamera_pad_get_pool(srcpad);\n+\n+\t\tif (pool) {\n+\t\t\tgst_libcamera_pool_set_buffer_notify(pool, NULL, NULL);\n+\t\t\tgst_libcamera_pad_set_pool(srcpad, NULL);\n+\t\t}\n+\t}\n \n \tg_clear_object(&self->allocator);\n \tg_clear_pointer(&self->flow_combiner,\n","prefixes":["libcamera-devel","v2","26/27"]}