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{ "id": 27114, "url": "https://patchwork.libcamera.org/api/patches/27114/?format=api", "web_url": "https://patchwork.libcamera.org/patch/27114/", "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": "<20260629163017.863145-36-barnabas.pocze@ideasonboard.com>", "date": "2026-06-29T16:29:58", "name": "[RFC,v1,35/54] libcamera: pipeline: uvcvideo: Use buffer pool prototype", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "18b475d146ccbd6352aaa3a008fcaecec7ce135e", "submitter": { "id": 216, "url": "https://patchwork.libcamera.org/api/people/216/?format=api", "name": "Barnabás Pőcze", "email": "barnabas.pocze@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/27114/mbox/", "series": [ { "id": 6025, "url": "https://patchwork.libcamera.org/api/series/6025/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=6025", "date": "2026-06-29T16:29:23", "name": "libcamera: Split requests and buffers", "version": 1, "mbox": "https://patchwork.libcamera.org/series/6025/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/27114/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/27114/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "X-Original-To": "parsemail@patchwork.libcamera.org", "Delivered-To": "parsemail@patchwork.libcamera.org", "Received": [ "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 63327C3261\n\tfor <parsemail@patchwork.libcamera.org>;\n\tMon, 29 Jun 2026 16:31:26 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id EF1D865F9B;\n\tMon, 29 Jun 2026 18:31:25 +0200 (CEST)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id BBDEF65F5E\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tMon, 29 Jun 2026 18:30:28 +0200 (CEST)", "from pb-laptop.local (185.221.140.128.nat.pool.zt.hu\n\t[185.221.140.128])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 98BEAE91\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tMon, 29 Jun 2026 18:29:45 +0200 (CEST)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"bgoTa776\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1782750585;\n\tbh=Y8L3gSLz9th3JTgFM5GAGAjtCWKQ7oKsE1dmWHmWxUA=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=bgoTa776n2SaY58TbMII4ORAnRHA1HZB9sXs3IK9RD9//qmfwJvbtMzpi/TewZKoS\n\tjteAxBYP4itLL1gheJ8DTwLrqXwqn+cAyFfPezmuuUIqOZqYQDeunX5B/oqWD4y4r+\n\to6zeuhVF2IZ68AS7YpanyThIbsC6IktyuetpmIeY=", "From": "=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= <barnabas.pocze@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Subject": "[RFC PATCH v1 35/54] libcamera: pipeline: uvcvideo: Use buffer pool\n\tprototype", "Date": "Mon, 29 Jun 2026 18:29:58 +0200", "Message-ID": "<20260629163017.863145-36-barnabas.pocze@ideasonboard.com>", "X-Mailer": "git-send-email 2.54.0", "In-Reply-To": "<20260629163017.863145-1-barnabas.pocze@ideasonboard.com>", "References": "<20260629163017.863145-1-barnabas.pocze@ideasonboard.com>", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=UTF-8", "Content-Transfer-Encoding": "8bit", "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>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "Convert the uvcvideo pipeline handler to use the buffer pool interface\nof cameras. Do that by keeping track of the number of queued buffers,\nand each time\n * a request is queued,\n * a buffer is added, or\n * a buffer is returned from the kernel\nthe pipeline handler tries to consume as many requests as possible.\n\nSigned-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>\n---\n src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 71 +++++++++++++++-----\n 1 file changed, 53 insertions(+), 18 deletions(-)", "diff": "diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp\nindex 928ee79559..e70cbe23c3 100644\n--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp\n+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp\n@@ -62,6 +62,8 @@ public:\n \tstd::optional<v4l2_exposure_auto_type> autoExposureMode_;\n \tstd::optional<v4l2_exposure_auto_type> manualExposureMode_;\n \n+\tsize_t processedRequests_ = 0;\n+\n private:\n \tbool generateId();\n \n@@ -95,6 +97,8 @@ public:\n \tvoid stopDevice(Camera *camera) override;\n \n \tint queueRequestDevice(Camera *camera, Request *request) override;\n+\tvoid buffersAddedDevice(Camera *camera) override;\n+\tvoid tryRunCamera(UVCCameraData *data);\n \n \tbool match(DeviceEnumerator *enumerator) override;\n \n@@ -230,7 +234,7 @@ CameraConfiguration::Status UVCCameraConfiguration::validate()\n }\n \n PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)\n-\t: PipelineHandler(manager, {})\n+\t: PipelineHandler(manager, { .usesBufferPool = true })\n {\n }\n \n@@ -323,6 +327,9 @@ void PipelineHandlerUVC::stopDevice(Camera *camera)\n \tUVCCameraData *data = cameraData(camera);\n \tdata->video_->streamOff();\n \tdata->video_->releaseBuffers();\n+\n+\twhile (!data->queuedRequests_.empty())\n+\t\tcancelRequest(data->queuedRequests_.front());\n }\n \n int PipelineHandlerUVC::processControl(const UVCCameraData *data, ControlList *controls,\n@@ -446,26 +453,49 @@ int PipelineHandlerUVC::processControls(UVCCameraData *data, const ControlList &\n \treturn ret;\n }\n \n-int PipelineHandlerUVC::queueRequestDevice(Camera *camera, Request *request)\n+int PipelineHandlerUVC::queueRequestDevice(Camera *camera, [[maybe_unused]] Request *request)\n {\n-\tUVCCameraData *data = cameraData(camera);\n-\tFrameBuffer *buffer = request->findBuffer(&data->stream_);\n-\tif (!buffer) {\n-\t\tLOG(UVC, Error)\n-\t\t\t<< \"Attempt to queue request with invalid stream\";\n+\t/* `request` is already in `Camera::Private::queuedRequests_` */\n+\ttryRunCamera(cameraData(camera));\n+\treturn 0;\n+}\n \n-\t\treturn -ENOENT;\n-\t}\n+void PipelineHandlerUVC::buffersAddedDevice(Camera *camera)\n+{\n+\ttryRunCamera(cameraData(camera));\n+}\n \n-\tint ret = processControls(data, request->controls());\n-\tif (ret < 0)\n-\t\treturn ret;\n+void PipelineHandlerUVC::tryRunCamera(UVCCameraData *data)\n+{\n+\tASSERT(data->processedRequests_ <= data->queuedRequests_.size());\n \n-\tret = data->video_->queueBuffer(buffer);\n-\tif (ret < 0)\n-\t\treturn ret;\n+\tauto it = std::next(data->queuedRequests_.begin(), data->processedRequests_);\n+\tfor (; it != data->queuedRequests_.end(); ++it, data->processedRequests_++) {\n+\t\tRequest *request = *it;\n+\t\tASSERT(request->status() == Request::RequestPending);\n \n-\treturn 0;\n+\t\tint ret = processControls(data, request->controls());\n+\t\tif (ret < 0) {\n+\t\t\tcancelRequest(request);\n+\t\t\tcontinue;\n+\t\t}\n+\n+again:;\n+\t\tauto buffer = data->acquireBuffer(&data->stream_);\n+\t\tif (!buffer)\n+\t\t\tbreak;\n+\n+\t\tret = data->video_->queueBuffer(buffer.get());\n+\t\tif (ret < 0) {\n+\t\t\t// \\todo do not do this if the error is \"too many buffers\"\n+\t\t\t// but that probably shouldn't ever be the case because\n+\t\t\t// VIDEO_MAX_FRAME == 32 == maxQueuedRequestsDevice\n+\t\t\tdata->rejectBuffer(std::move(buffer));\n+\t\t\tgoto again;\n+\t\t}\n+\n+\t\tbuffer.release();\n+\t}\n }\n \n bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)\n@@ -893,14 +923,19 @@ void UVCCameraData::addControl(uint32_t cid, const ControlInfo &v4l2Info,\n \n void UVCCameraData::imageBufferReady(FrameBuffer *buffer)\n {\n-\tRequest *request = buffer->_d()->request();\n+\tASSERT(!queuedRequests_.empty());\n+\tASSERT(processedRequests_ > 0);\n+\n+\tRequest *request = queuedRequests_.front();\n \n \t/* \\todo Use the UVC metadata to calculate a more precise timestamp */\n \trequest->_d()->metadata().set(controls::SensorTimestamp,\n \t\t\t\t buffer->metadata().timestamp);\n \n \tpipe()->completeBuffer(request, buffer);\n-\tpipe()->completeRequest(request);\n+\tprocessedRequests_ -= pipe()->completeRequest(request);\n+\n+\tstatic_cast<PipelineHandlerUVC *>(pipe())->tryRunCamera(this);\n }\n \n REGISTER_PIPELINE_HANDLER(PipelineHandlerUVC, \"uvcvideo\")\n", "prefixes": [ "RFC", "v1", "35/54" ] }