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{ "id": 2221038, "url": "http://patchwork.ozlabs.org/api/1.1/covers/2221038/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/cover/20260409-ls7a-bridge-fixes-v1-0-3650fedf1afc@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-v1-0-3650fedf1afc@rong.moe>", "date": "2026-04-08T17:56:56", "name": "[0/2] PCI: loongson: Do not ignore downstream devices on external bridges", "submitter": { "id": 87882, "url": "http://patchwork.ozlabs.org/api/1.1/people/87882/?format=api", "name": "Rong Zhang", "email": "i@rong.moe" }, "mbox": "http://patchwork.ozlabs.org/project/linux-pci/cover/20260409-ls7a-bridge-fixes-v1-0-3650fedf1afc@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/covers/2221038/comments/", "headers": { "Return-Path": "\n <linux-pci+bounces-52168-incoming=patchwork.ozlabs.org@vger.kernel.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linux-pci@vger.kernel.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=rong.moe header.i=i@rong.moe header.a=rsa-sha256\n header.s=zmail2048 header.b=GjPFp+7z;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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arc=pass smtp.client-ip=136.143.188.15", "i=1; mx.zohomail.com;\n\tdkim=pass header.i=rong.moe;\n\tspf=pass smtp.mailfrom=i@rong.moe;\n\tdmarc=pass header.from=<i@rong.moe>" ], "DKIM-Signature": "v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1775671041;\n\ts=zmail2048; d=rong.moe; i=i@rong.moe;\n\th=From:From:Subject:Subject:Date:Date:Message-Id:Message-Id:MIME-Version:Content-Type:Content-Transfer-Encoding:To:To:Cc:Cc:Reply-To;\n\tbh=p4pF/F9iArMybAchaDSsfxBcz1TRYzAHsA/fPnJEh7Q=;\n\tb=GjPFp+7zMBflyY0tAme4KCFoFIJ3+aQ5+f9umJ7zDW5OkOTwjU0yTRIO7dh20y3I\n\tKXgaoUZcWfNt2PhezJ5Aa4t6Ke+ewQUTDw67D5hx3xx0/3mjorD09BiS4YDIFB4A6Hx\n\tNVMquKKxiveILly4aK4f3m6WhiGu9WUtAXBM0YRKsqH6ksfUYJKujsD12l0DGVe6+Wl\n\tF8TwGA30YqMjmazWPwwEBKstrap6GTyfEGsm9iuUQT2qhK3WvI598B3gqn8P1xlbjXF\n\tU5cOOA+HOZk3x6n6ivcWGhQKuTTIve2dYg6RCxNLtul8pPuLZD7X5w0Bpwtj7lQEIOm\n\tmQhE95Butw==", "From": "Rong Zhang <i@rong.moe>", "Subject": "[PATCH 0/2] PCI: loongson: Do not ignore downstream devices on\n external bridges", "Date": "Thu, 09 Apr 2026 01:56:56 +0800", "Message-Id": "<20260409-ls7a-bridge-fixes-v1-0-3650fedf1afc@rong.moe>", "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", "X-B4-Tracking": "v=1; b=H4sIAOiW1mkC/yWMywrCMBAAf6XsuYEY0pj6K8VDHquulCjZKkLIv\n 3fV4zDMNGCshAynoUHFNzE9isBhHCDdQrmioiwMRhunrfZq5WNQsVIWdaEPsvJhjpMNLjqTQLp\n nxZ+QbDn/mV/xjmn7jqD3HWQdQph1AAAA", "X-Change-ID": "20260408-ls7a-bridge-fixes-8a9b54a6b62c", "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---\nRong Zhang (2):\n PCI: loongson: Move bridge device ids to file scope\n PCI: loongson: Do not ignore downstream devices on external bridges\n\n drivers/pci/controller/pci-loongson.c | 31 ++++++++++++++++---------------\n 1 file changed, 16 insertions(+), 15 deletions(-)\n---\nbase-commit: 3036cd0d3328220a1858b1ab390be8b562774e8a\nchange-id: 20260408-ls7a-bridge-fixes-8a9b54a6b62c\n\nThanks,\nRong" }