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GET /api/1.1/patches/2221039/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 2221039,
    "url": "http://patchwork.ozlabs.org/api/1.1/patches/2221039/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/linux-pci/patch/20260409-ls7a-bridge-fixes-v1-2-3650fedf1afc@rong.moe/",
    "project": {
        "id": 28,
        "url": "http://patchwork.ozlabs.org/api/1.1/projects/28/?format=api",
        "name": "Linux PCI development",
        "link_name": "linux-pci",
        "list_id": "linux-pci.vger.kernel.org",
        "list_email": "linux-pci@vger.kernel.org",
        "web_url": null,
        "scm_url": null,
        "webscm_url": null
    },
    "msgid": "<20260409-ls7a-bridge-fixes-v1-2-3650fedf1afc@rong.moe>",
    "date": "2026-04-08T17:56:58",
    "name": "[2/2] PCI: loongson: Do not ignore downstream devices on external bridges",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "0747e15c879e4e92fa12d48f9a5cdf5ace81d1ae",
    "submitter": {
        "id": 87882,
        "url": "http://patchwork.ozlabs.org/api/1.1/people/87882/?format=api",
        "name": "Rong Zhang",
        "email": "i@rong.moe"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/linux-pci/patch/20260409-ls7a-bridge-fixes-v1-2-3650fedf1afc@rong.moe/mbox/",
    "series": [
        {
            "id": 499173,
            "url": "http://patchwork.ozlabs.org/api/1.1/series/499173/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/linux-pci/list/?series=499173",
            "date": "2026-04-08T17:56:57",
            "name": "PCI: loongson: Do not ignore downstream devices on external bridges",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/499173/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2221039/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2221039/checks/",
    "tags": {},
    "headers": {
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        ],
        "DKIM-Signature": "v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1775671047;\n\ts=zmail2048; d=rong.moe; i=i@rong.moe;\n\th=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To;\n\tbh=COxeKDaX+XgKV90LR9TylYsK00hAyP3GSYBqn/E/Jzc=;\n\tb=l3XNOglIfOzSCm5bFTlmolTMycT7nLvoW4Ifh0HfS6RKlUrmL90i1Aib5ziIRhmA\n\tajnJ+qTvunHg/PvWssGonXnikoBh3zehXEIEdXU3i6bw5dPXEz+KNBUBVjTT5OKWHJN\n\tW3XSY6EW85RlIa8YWR+RBpBRRRH83laFF3YfdnI1ktAW4Pg2Tt0oWHK/L9FRE9v0ESJ\n\tA+/eR8JFhccUfTgZRiAG2S11DCWkQmY1qUCLBX+jFxDsaGM8xm9YUsvBbZAD9wBX9v7\n\tAFC2/yY5rTKL5tyDwI20Hchqiqc3DpUP8CDWuVqK2xY5RYOJDVYUMhJlV89fBJBx8pm\n\trBNOp56jEA==",
        "From": "Rong Zhang <i@rong.moe>",
        "Date": "Thu, 09 Apr 2026 01:56:58 +0800",
        "Subject": "[PATCH 2/2] PCI: loongson: Do not ignore downstream devices on\n external bridges",
        "Precedence": "bulk",
        "X-Mailing-List": "linux-pci@vger.kernel.org",
        "List-Id": "<linux-pci.vger.kernel.org>",
        "List-Subscribe": "<mailto:linux-pci+subscribe@vger.kernel.org>",
        "List-Unsubscribe": "<mailto:linux-pci+unsubscribe@vger.kernel.org>",
        "MIME-Version": "1.0",
        "Content-Type": "text/plain; charset=\"utf-8\"",
        "Content-Transfer-Encoding": "7bit",
        "Message-Id": "<20260409-ls7a-bridge-fixes-v1-2-3650fedf1afc@rong.moe>",
        "References": "<20260409-ls7a-bridge-fixes-v1-0-3650fedf1afc@rong.moe>",
        "In-Reply-To": "<20260409-ls7a-bridge-fixes-v1-0-3650fedf1afc@rong.moe>",
        "To": "Lorenzo Pieralisi <lpieralisi@kernel.org>, =?utf-8?q?Krzysztof_Wilczy?=\n\t=?utf-8?q?=C5=84ski?= <kwilczynski@kernel.org>,\n  Manivannan Sadhasivam <mani@kernel.org>, Rob Herring <robh@kernel.org>,\n  Bjorn Helgaas <bhelgaas@google.com>, Huacai Chen <chenhuacai@kernel.org>",
        "Cc": "linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,\n Jiaxun Yang <jiaxun.yang@flygoat.com>,\n \"Lain \\\"Fearyncess\\\" Yang\" <i@lain.vg>, Rong Zhang <i@rong.moe>",
        "X-Mailer": "b4 0.16-dev-7777e",
        "X-ZohoMailClient": "External"
    },
    "content": "Loongson PCI host controllers have a hardware quirk that requires\nsoftware to ignore downstream devices with device number > 0 on the\ninternal bridges. The current implementation applies the workaround to\nall non-root buses, which breaks external bridges (e.g., PCIe switches)\nwith multiple downstream devices.\n\nFix it by only applying the workaround to internal bridges.\n\nTested on Loongson-LS3A4000-7A1000-NUC-SE, using AMD Promontory 21\nchipset add-in card [1].\n\n  $ lspci -tnnnvvv\n  -[0000:00]-+-00.0  Loongson Technology LLC 7A1000 Chipset Hyper Transport Bridge Controller [0014:7a00]\n             +-00.1  Loongson Technology LLC 7A2000 Chipset Hyper Transport Bridge Controller [0014:7a10]\n             +-03.0  Loongson Technology LLC 2K1000/2000 / 7A1000 Chipset Gigabit Ethernet Controller [0014:7a03]\n             +-04.0  Loongson Technology LLC 2K1000 / 7A1000/2000 Chipset USB OHCI Controller [0014:7a24]\n             +-04.1  Loongson Technology LLC 2K1000 / 7A1000/2000 Chipset USB EHCI Controller [0014:7a14]\n             +-05.0  Loongson Technology LLC 2K1000 / 7A1000/2000 Chipset USB OHCI Controller [0014:7a24]\n             +-05.1  Loongson Technology LLC 2K1000 / 7A1000/2000 Chipset USB EHCI Controller [0014:7a14]\n             +-06.0  Loongson Technology LLC 7A1000 Chipset Vivante GC1000 GPU [0014:7a15]\n             +-06.1  Loongson Technology LLC 2K1000 / 7A1000 Chipset Display Controller [0014:7a06]\n             +-07.0  Loongson Technology LLC 2K1000/2000/3000 / 3B6000M / 7A1000/2000 Chipset HD Audio Controller [0014:7a07]\n             +-08.0  Loongson Technology LLC 2K1000 / 7A1000 Chipset 3Gb/s SATA AHCI Controller [0014:7a08]\n             +-08.1  Loongson Technology LLC 2K1000 / 7A1000 Chipset 3Gb/s SATA AHCI Controller [0014:7a08]\n             +-08.2  Loongson Technology LLC 2K1000 / 7A1000 Chipset 3Gb/s SATA AHCI Controller [0014:7a08]\n             +-09.0-[01]----00.0  Qualcomm Technologies, Inc QCNFA765 Wireless Network Adapter [17cb:1103]\n             +-0a.0-[02]----00.0  Etron Technology, Inc. EJ188/EJ198 USB 3.0 Host Controller [1b6f:7052]\n             +-0f.0-[03-08]----00.0-[04-08]--+-00.0-[05]----00.0  Shenzhen Longsys Electronics Co., Ltd. FORESEE XP1000 / Lexar Professional CFexpress Type B Gold series, NM620 PCIe NVME SSD (DRAM-less) [1d97:5216]\n             |                               +-08.0-[06]----00.0  MAXIO Technology (Hangzhou) Ltd. NVMe SSD Controller MAP1202 (DRAM-less) [1e4b:1202]\n             |                               +-0c.0-[07]----00.0  Advanced Micro Devices, Inc. [AMD] 600 Series Chipset USB 3.2 Controller [1022:43f7]\n             |                               \\-0d.0-[08]----00.0  Advanced Micro Devices, Inc. [AMD] 600 Series Chipset SATA Controller [1022:43f6]\n             \\-16.0  Loongson Technology LLC 7A1000 Chipset SPI Controller [0014:7a0b]\n\nFixes: 2410e3301fcc (\"PCI: loongson: Don't access non-existent devices\")\nLink: https://oshwhub.com/wesd/b650 [1]\nCo-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>\nSigned-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>\nCo-developed-by: Lain \"Fearyncess\" Yang <i@lain.vg>\nSigned-off-by: Lain \"Fearyncess\" Yang <i@lain.vg>\nSigned-off-by: Rong Zhang <i@rong.moe>\n---\n drivers/pci/controller/pci-loongson.c | 6 +++---\n 1 file changed, 3 insertions(+), 3 deletions(-)",
    "diff": "diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c\nindex 8b1a3a03dc51..de5e809a537d 100644\n--- a/drivers/pci/controller/pci-loongson.c\n+++ b/drivers/pci/controller/pci-loongson.c\n@@ -231,11 +231,11 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus,\n \tstruct loongson_pci *priv = pci_bus_to_loongson_pci(bus);\n \n \t/*\n-\t * Do not read more than one device on the bus other than\n-\t * the host bus.\n+\t * Do not read more than one device on the internal bridges.\n \t */\n \tif ((priv->data->flags & FLAG_DEV_FIX) && bus->self) {\n-\t\tif (!pci_is_root_bus(bus) && (device > 0))\n+\t\tif (!pci_is_root_bus(bus) && (device > 0) &&\n+\t\t    pci_match_id(loongson_internal_bridge_devids, bus->self))\n \t\t\treturn NULL;\n \t}\n \n",
    "prefixes": [
        "2/2"
    ]
}