{"id":3940,"url":"https://patchwork.libcamera.org/api/1.1/patches/3940/?format=json","web_url":"https://patchwork.libcamera.org/patch/3940/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/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":"<20200605090106.15424-6-paul.elder@ideasonboard.com>","date":"2020-06-05T09:01:04","name":"[libcamera-devel,v2,5/7] v4l2: v4l2_camera_proxy: Don't return -EINVAL for zero sizeimage in REQBUFS","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"f3895414e9b64b676a15cb4e6f04677348fa08ea","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/1.1/people/17/?format=json","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/3940/mbox/","series":[{"id":956,"url":"https://patchwork.libcamera.org/api/1.1/series/956/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=956","date":"2020-06-05T09:00:59","name":"Support qv4l2 with v4l2-compat","version":2,"mbox":"https://patchwork.libcamera.org/series/956/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/3940/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/3940/checks/","tags":{},"headers":{"Return-Path":"","Received":["from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 006EE6124F\n\tfor ;\n\tFri, 5 Jun 2020 11:01:24 +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 CD86F27C;\n\tFri, 5 Jun 2020 11:01:22 +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=\"lsl5tw/y\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1591347683;\n\tbh=eqVGWxLcEElmdrGmRBqiyy8NYrlqldzJ/gMwEMcKe1c=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=lsl5tw/yoUsF3yW/pfke3lz+9DNju3R5uvrgkR0bnt9/CpjWmPIm6WIi/Bh+7HdGw\n\t1cxW4w8/plWitFl9IwG/93G9DQ461Xs1WHaCCRW3KnXTgwSO51X4C4rCQOwFDICClY\n\tRH5GI5UPZxjTYRSpcVx06ZorxtoQelD5Tv+AHGi0=","From":"Paul Elder ","To":"libcamera-devel@lists.libcamera.org","Date":"Fri, 5 Jun 2020 18:01:04 +0900","Message-Id":"<20200605090106.15424-6-paul.elder@ideasonboard.com>","X-Mailer":"git-send-email 2.20.1","In-Reply-To":"<20200605090106.15424-1-paul.elder@ideasonboard.com>","References":"<20200605090106.15424-1-paul.elder@ideasonboard.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v2 5/7] v4l2: v4l2_camera_proxy: Don't\n\treturn -EINVAL for zero sizeimage in REQBUFS","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 09:01:24 -0000"},"content":"If VIDIOC_REQBUFS returns -EINVAL, it signals to the application that\nthe requested buffer or memory type is not supported. If we return\n-EINVAL due to a zero sizeimage, then the application will think that we\ndon't support a memory type that we actually do. We cannot error on a\nzero sizeimage, because reqbufs could be called merely to probe what IO\nmethods we support; qv4l2, for example, called reqbufs once with userptr\nand once more with mmap, both times with count=1.\n\nOn the other hand, sizeimage will be zero for formats whose size we\ndon't know how to calculate, such as MJPEG. If we try to stream such\nformats anyway, we will get a floating point exception and crash. Issue\na warning for now, and don't return -EINVAL, so that we can continue\noperation.\n\nSigned-off-by: Paul Elder \n\n---\nChanges in v2: expand changelog\n---\n src/v4l2/v4l2_camera_proxy.cpp | 12 +++++++++++-\n 1 file changed, 11 insertions(+), 1 deletion(-)","diff":"diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\nindex a0c6deea..cbe9e026 100644\n--- a/src/v4l2/v4l2_camera_proxy.cpp\n+++ b/src/v4l2/v4l2_camera_proxy.cpp\n@@ -352,8 +352,18 @@ int V4L2CameraProxy::vidioc_reqbufs(struct v4l2_requestbuffers *arg)\n \t\treturn -EINVAL;\n \n \tsizeimage_ = calculateSizeImage(streamConfig_);\n+\t/*\n+\t * If we return -EINVAL here then the application will think that we\n+\t * don't support streaming mmap. Since we don't support readwrite and\n+\t * userptr either, the application will get confused and think that\n+\t * we don't support anything.\n+\t * On the other hand, if a format has a zero sizeimage (eg. MJPEG),\n+\t * we'll get a floating point exception when we try to stream it.\n+\t */\n \tif (sizeimage_ == 0)\n-\t\treturn -EINVAL;\n+\t\tLOG(V4L2Compat, Warning)\n+\t\t\t<< \"sizeimage of at least one format is zero. \"\n+\t\t\t<< \"Streaming this format will cause a floating point exception.\";\n \n \tsetFmtFromConfig(streamConfig_);\n \n","prefixes":["libcamera-devel","v2","5/7"]}