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GET /api/1.1/patches/2229302/?format=api
{ "id": 2229302, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2229302/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/patch/20260428040104.78524-1-carlos.bilbao@kernel.org/", "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": "<20260428040104.78524-1-carlos.bilbao@kernel.org>", "date": "2026-04-28T04:01:04", "name": "PCI/ASPM: Don't reconfigure ASPM entering low-power state", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "0694b0082a5436e00b0f201c007b6991ad5ca68a", "submitter": { "id": 93050, "url": "http://patchwork.ozlabs.org/api/1.1/people/93050/?format=api", "name": "Carlos Bilbao (Lambda)", "email": "carlos.bilbao@kernel.org" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linux-pci/patch/20260428040104.78524-1-carlos.bilbao@kernel.org/mbox/", "series": [ { "id": 501759, "url": "http://patchwork.ozlabs.org/api/1.1/series/501759/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/list/?series=501759", "date": "2026-04-28T04:01:04", "name": "PCI/ASPM: Don't reconfigure ASPM entering low-power state", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/501759/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2229302/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2229302/checks/", "tags": {}, "headers": { "Return-Path": "\n <linux-pci+bounces-53303-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=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=aeoHnv+/;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c15:e001:75::12fc:5321; helo=sin.lore.kernel.org;\n envelope-from=linux-pci+bounces-53303-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)", "smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"aeoHnv+/\"", "smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201" ], "Received": [ "from sin.lore.kernel.org (sin.lore.kernel.org\n [IPv6:2600:3c15:e001:75::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g4Rd65VvYz1yHv\n\tfor <incoming@patchwork.ozlabs.org>; Tue, 28 Apr 2026 14:03:54 +1000 (AEST)", "from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sin.lore.kernel.org (Postfix) with ESMTP id B8D8D3005147\n\tfor <incoming@patchwork.ozlabs.org>; Tue, 28 Apr 2026 04:01:14 +0000 (UTC)", "from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id AFA9F3002AB;\n\tTue, 28 Apr 2026 04:01:11 +0000 (UTC)", "from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 8CFEB40DFD3;\n\tTue, 28 Apr 2026 04:01:11 +0000 (UTC)", "by smtp.kernel.org (Postfix) with ESMTPSA id BE1C5C2BCAF;\n\tTue, 28 Apr 2026 04:01:10 +0000 (UTC)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1777348871; cv=none;\n b=iGGU/duC5Wv7zH/b4SefTFGuf7+fQLwkDDvauriZQ9DNhl/kLE8zLCVIjzl2oPzdbigF4xpYuM5CYXyzhpV+ZVjYiDynu5KLgqu7kilXnJ0ynqwk7wZKN8pi6Xr36E1/JLFbrokLhA11KLlUUTgNgtZoWgfaTXJiE9T94mTc84M=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1777348871; c=relaxed/simple;\n\tbh=6yJDQrFYOnSimHYpjK9gZ6lZp3jY/9xvbZuj1IWjkWE=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=Im+ib5GJ4wNvKKAJNm4po8IqLeZGK9SPJLhp6WlpTrK2gyM/MnZLnPei8ph3eAIC36OQXze99vukRpX+czN+P4efCmX0DlA+nMdY72SW9q18QcaQ6tbCQfnZZkCV0tVS+ddaF3m755ho8h7oMKeaiciUv58BG5ifqYMYWA3cFTc=", "ARC-Authentication-Results": "i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=aeoHnv+/; arc=none smtp.client-ip=10.30.226.201", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1777348871;\n\tbh=6yJDQrFYOnSimHYpjK9gZ6lZp3jY/9xvbZuj1IWjkWE=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=aeoHnv+/fK/IjbEEmCfCOIYlwLOzgRnqb6yUYHIwx3hc8aLdXi6iypqDi/R6K+PrI\n\t Dlj7A68pqvo1SAiEYzMJvZXkt5CcSyHohtUe5jhjfIOV3TFCtkU93RO8I/vrjPHFSN\n\t 2KOR4JSSIGmVez3Jlghd4MQ1U+02WTCnxPi1pIWv1l/CCFC7vrjZ/FTdbckU5hWq7t\n\t 4h3+wlPeSrxrKr345oGkg4YaxkiCmHRbLE0LIctAUA26DLGcBMAWpIaza+jIvXj/zc\n\t K2PclFDbOAgD1Cc0xrtpSzvut1y8KkmPMyXs+DCbwc6SP3zQiANDTgZtpdAQf2eK9u\n\t GxbQqKWCwpTVw==", "From": "\"Carlos Bilbao (Lambda)\" <carlos.bilbao@kernel.org>", "To": "bhelgaas@google.com", "Cc": "eduardo.habkost@lambdal.com,\n\tlinux-pci@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org,\n\tbilbao@vt.edu,\n\tCarlos Bilbao <carlos.bilbao@kernel.org>", "Subject": "[PATCH] PCI/ASPM: Don't reconfigure ASPM entering low-power state", "Date": "Mon, 27 Apr 2026 21:01:04 -0700", "Message-ID": "<20260428040104.78524-1-carlos.bilbao@kernel.org>", "X-Mailer": "git-send-email 2.43.0", "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-Transfer-Encoding": "8bit" }, "content": "From: Carlos Bilbao <carlos.bilbao@kernel.org>\n\nReconfiguring ASPM when a device transitions to low-power state can enable\nL1.1/L1.2 substates on the PCIe link at a time when the device is sleeping\nand may be unable to exit them. ASPM should be reconfigured on D0 entry\n(resume), not on the way down.\n\npci_set_low_power_state() calls pcie_aspm_pm_state_change() after writing\nD3hot to PCI_PM_CTRL. pcie_aspm_pm_state_change() resets link->aspm_capable\nto link->aspm_support and then calls pcie_config_aspm_path(), which can\nenable ASPM L1.1/L1.2 substates on the PCIe link. If the device cannot\nrecover the link from L1.2 while in D3hot, subsequent config space reads\nreturn 0xFFFF (\"device inaccessible\") and pci_power_up() fails with message\n\"Unable to change power state from D3hot to D0, device inaccessible\".\n\nThis was observed on NVIDIA H100 SXM5 GPUs bound to vfio-pci when Linux\nruntime PM suspends them to D3hot: the GPU becomes permanently inaccessible\nand disappears from the PCIe bus.\n\nThe call to pcie_aspm_pm_state_change() in pci_set_low_power_state() was\nrestored by commit f93e71aea6c6 (\"Revert \"PCI/ASPM: Remove\npcie_aspm_pm_state_change()\"\"), which reverted\ncommit 08d0cc5f3426 (\"PCI/ASPM: Remove pcie_aspm_pm_state_change()\").\nThe revert was necessary because the\nremoval broke suspend/resume on certain platforms that required ASPM to be\nreconfigured on D0 entry. However, the revert restored the call in both\npci_set_full_power_state() (D0 entry) and pci_set_low_power_state()\n(low-power entry).\n\nOnly the D0-entry call is needed to fix the suspend/resume regression. The\nlow-power-entry call is harmful: reconfiguring ASPM immediately after\nputting a device into D3hot can enable link substates that the device or\nplatform cannot exit while the device is sleeping.\n\nRemove the pcie_aspm_pm_state_change() call from pci_set_low_power_state().\nASPM will still be reconfigured correctly when the device returns to D0 via\npci_set_full_power_state().\n\nFixes: f93e71aea6c6 (\"Revert \"PCI/ASPM: Remove pcie_aspm_pm_state_change()\"\")\nLink: https://lore.kernel.org/r/20240102232550.1751655-1-helgaas@kernel.org\nSigned-off-by: Carlos Bilbao (Lambda) <carlos.bilbao@kernel.org>\n---\n drivers/pci/pci.c | 3 ---\n 1 file changed, 3 deletions(-)", "diff": "diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c\nindex b2ccb8e122f2..8b47887019f9 100644\n--- a/drivers/pci/pci.c\n+++ b/drivers/pci/pci.c\n@@ -1542,9 +1542,6 @@ static int pci_set_low_power_state(struct pci_dev *dev, pci_power_t state, bool\n \t\t\t\t pci_power_name(dev->current_state),\n \t\t\t\t pci_power_name(state));\n \n-\tif (dev->bus->self)\n-\t\tpcie_aspm_pm_state_change(dev->bus->self, locked);\n-\n \treturn 0;\n }\n \n", "prefixes": [] }