Show a cover letter.

GET /api/1.1/covers/11480/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 11480,
    "url": "https://patchwork.libcamera.org/api/1.1/covers/11480/?format=api",
    "web_url": "https://patchwork.libcamera.org/cover/11480/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/1.1/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": "<20210303170426.189648-1-kieran.bingham@ideasonboard.com>",
    "date": "2021-03-03T17:04:23",
    "name": "[libcamera-devel,0/3] IPU3 Stability",
    "submitter": {
        "id": 4,
        "url": "https://patchwork.libcamera.org/api/1.1/people/4/?format=api",
        "name": "Kieran Bingham",
        "email": "kieran.bingham@ideasonboard.com"
    },
    "mbox": "https://patchwork.libcamera.org/cover/11480/mbox/",
    "series": [
        {
            "id": 1754,
            "url": "https://patchwork.libcamera.org/api/1.1/series/1754/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=1754",
            "date": "2021-03-03T17:04:23",
            "name": "IPU3 Stability",
            "version": 1,
            "mbox": "https://patchwork.libcamera.org/series/1754/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/covers/11480/comments/",
    "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 A5B57BD1F1\n\tfor <parsemail@patchwork.libcamera.org>;\n\tWed,  3 Mar 2021 17:04:31 +0000 (UTC)",
            "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 2BE9D68A9A;\n\tWed,  3 Mar 2021 18:04:31 +0100 (CET)",
            "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 BAD1868A7E\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tWed,  3 Mar 2021 18:04:29 +0100 (CET)",
            "from Q.local (cpc89244-aztw30-2-0-cust3082.18-1.cable.virginm.net\n\t[86.31.172.11])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 334C68CA;\n\tWed,  3 Mar 2021 18:04:29 +0100 (CET)"
        ],
        "Authentication-Results": "lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"eQH9NhWt\"; dkim-atps=neutral",
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1614791069;\n\tbh=kxQxlT+lrxej072+vlEhrUPeDgjqoG4oz3kLgaHiRN8=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=eQH9NhWtsZeq12ilxyb/FCZwsm5TvFDFOvR9uGS0sj3+0wWGO1HPnI4DYKd+fKnuu\n\tx2/7whIywUYu/ezKPwluWqqs76Sr/f6UCMlUba1YYILbygYs51vAWvVIwKVCH1rrpN\n\tm8q1ymQ5XlDW87/6tY7u1t0jt9EusfWzBw9o67Ds=",
        "From": "Kieran Bingham <kieran.bingham@ideasonboard.com>",
        "To": "libcamera devel <libcamera-devel@lists.libcamera.org>",
        "Date": "Wed,  3 Mar 2021 17:04:23 +0000",
        "Message-Id": "<20210303170426.189648-1-kieran.bingham@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.25.1",
        "MIME-Version": "1.0",
        "Subject": "[libcamera-devel] [PATCH 0/3] IPU3 Stability",
        "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>",
        "Content-Type": "text/plain; charset=\"us-ascii\"",
        "Content-Transfer-Encoding": "7bit",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "While working on the IPU3 IPA, some crashes have been occuring on\nshutdown races.\n\nPatches 2/3 and 3/3 at least presently work around those issues, and\nwhile they may be suitable for integration now - both suggest that more\nwork is needed to ensure that the IPU3 pipeline handler is stable and\nimplemented correctly.\n\nPatch 2/3 highlights that we may need to take more concern over the\nlifetime management of a Request and the associated FrameInfo that is\nsupported with that.\n\nPatch 3/3 shows that the IPU3 Pipeline handler is queueing buffers after\nit has released the buffers on the video nodes, and needs further\nconsideration as well (though I beleive that patch is still worthy of\nintegration on it's own).\n\nThe issue leading to what would be a crash without patch 3/3 is when\nshutting down, the IPA running in parallel can emit an event from:\n void IPU3CameraData::queueFrameAction()\nas \n\n  case ipa::ipu3::ActionParamFilled:\n\nwhich then goes on to queue a buffer to the three relevant V4L2 devices:\n\n\timgu_->param_->queueBuffer(info->paramBuffer);\n\timgu_->stat_->queueBuffer(info->statBuffer);\n\timgu_->input_->queueBuffer(info->rawBuffer);\n\n\nThis is occuring after those devices have released their buffers, and\nthus the v4l2 buffer cache (cache_) is deleted and set to nullptr,\nresulting in a segmentation fault within the V4L2VideoDevice otherwise.\n\n\n\nKieran Bingham (3):\n  libcamera: pipeline: ipu3: Fix spelling error\n  libcamera: pipeline: ipu3: Ensure that IPU3Frames::info is not used\n    after delete\n  libcamera: v4l2_videodevice: Prevent queueing buffers without a cache\n\n src/libcamera/pipeline/ipu3/frames.cpp |  2 +-\n src/libcamera/pipeline/ipu3/ipu3.cpp   | 20 ++++++++++++++++++--\n src/libcamera/v4l2_videodevice.cpp     | 10 ++++++++++\n 3 files changed, 29 insertions(+), 3 deletions(-)"
}