{"id":2230416,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2230416/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260429180647.197072-4-thomas.falcon@intel.com/","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/1.1/projects/28/?format=json","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":"<20260429180647.197072-4-thomas.falcon@intel.com>","date":"2026-04-29T18:06:45","name":"[RFC,3/4] pcie/aspm: Enable all hardware power-saving states by default","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"d8341a3b9b8d284e9c7daa5e1e3a77fabc673691","submitter":{"id":93044,"url":"http://patchwork.ozlabs.org/api/1.1/people/93044/?format=json","name":"Falcon, Thomas","email":"thomas.falcon@intel.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260429180647.197072-4-thomas.falcon@intel.com/mbox/","series":[{"id":502124,"url":"http://patchwork.ozlabs.org/api/1.1/series/502124/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/list/?series=502124","date":"2026-04-29T18:06:44","name":"pcie/aspm: Enable all advertised ASPM states by default","version":1,"mbox":"http://patchwork.ozlabs.org/series/502124/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2230416/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2230416/checks/","tags":{},"headers":{"Return-Path":"\n ","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=intel.com header.i=@intel.com header.a=rsa-sha256\n header.s=Intel header.b=RxAfiXc2;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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a=\"78532284\"","E=Sophos;i=\"6.23,206,1770624000\";\n d=\"scan'208\";a=\"78532284\""],"X-ExtLoop1":"1","From":"Thomas Falcon ","To":"Bjorn Helgaas ,\n\t\"Rafael J . Wysocki\" ","Cc":"\"David E . Box\" ,\n\tLukas Wunner ,\n\tManivannan Sadhasivam ,\n\tLen Brown ,\n\tlinux-pci@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org,\n\tThomas Falcon ","Subject":"[RFC PATCH 3/4] pcie/aspm: Enable all hardware power-saving states by\n default","Date":"Wed, 29 Apr 2026 13:06:45 -0500","Message-ID":"<20260429180647.197072-4-thomas.falcon@intel.com>","X-Mailer":"git-send-email 2.43.0","In-Reply-To":"<20260429180647.197072-1-thomas.falcon@intel.com>","References":"<20260429180647.197072-1-thomas.falcon@intel.com>","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit"},"content":"For systems with a BIOS release date starting in 2025, default\nASPM policy to powersupersave if supported in the ACPI FADT.\nProvide a flag, aspm_user_policy, tracking whether a user has\nrequested a specific power state to give those precedence.\nDo not enable all states if user has chosen a specific policy\nor disabled ASPM using the pcie_aspm module parameter.\n\nSuggested-by: David E. Box \nSigned-off-by: Thomas Falcon \n---\n drivers/pci/pci-acpi.c | 4 +++-\n drivers/pci/pcie/aspm.c | 17 +++++++++++++++++\n include/linux/pci.h | 1 +\n 3 files changed, 21 insertions(+), 1 deletion(-)","diff":"diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c\nindex 4d0f2cb6c695..d849bc6d0c0c 100644\n--- a/drivers/pci/pci-acpi.c\n+++ b/drivers/pci/pci-acpi.c\n@@ -1523,7 +1523,9 @@ static int __init acpi_pci_init(void)\n \tif (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {\n \t\tpr_info(\"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\\n\");\n \t\tpcie_no_aspm();\n-\t}\n+\t} else\n+\t\t/* If ASPM is supported, configure the default policy here. */\n+\t\tpcie_aspm_policy_config_init();\n \n \tif (acpi_pci_disabled)\n \t\treturn 0;\ndiff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c\nindex 84d49aa8a5ba..1c81e2f2e589 100644\n--- a/drivers/pci/pcie/aspm.c\n+++ b/drivers/pci/pcie/aspm.c\n@@ -267,6 +267,8 @@ static int aspm_policy = POLICY_POWER_SUPERSAVE;\n #else\n static int aspm_policy;\n #endif\n+static int aspm_default_policy = POLICY_POWER_SUPERSAVE;\n+static bool aspm_user_policy;\n \n static const char *policy_str[] = {\n \t[POLICY_DEFAULT] = \"default\",\n@@ -1609,6 +1611,7 @@ static int pcie_aspm_set_policy(const char *val,\n \tdown_read(&pci_bus_sem);\n \tmutex_lock(&aspm_lock);\n \taspm_policy = i;\n+\taspm_user_policy = true;\n \tlist_for_each_entry(link, &link_list, sibling) {\n \t\tpcie_config_aspm_link(link, policy_to_aspm_state(link));\n \t\tpcie_set_clkpm(link, policy_to_clkpm_state(link));\n@@ -1810,6 +1813,20 @@ static int __init pcie_aspm_disable(char *str)\n \n __setup(\"pcie_aspm=\", pcie_aspm_disable);\n \n+\n+\n+void __init pcie_aspm_policy_config_init(void)\n+{\n+\t/*\n+\t * Set ASPM policy here, enabling all power-saving states\n+\t * unless ASPM has been disabled or the user has already\n+\t * requested a policy or the systems BIOS release date\n+\t * is before the year 2025. Otherwise use BIOS defaults.\n+\t */\n+\tif (!aspm_disabled && !aspm_user_policy && dmi_get_bios_year() >= 2025)\n+\t\taspm_policy = aspm_default_policy;\n+}\n+\n void pcie_no_aspm(void)\n {\n \t/*\ndiff --git a/include/linux/pci.h b/include/linux/pci.h\nindex 2c4454583c11..36fa5579709c 100644\n--- a/include/linux/pci.h\n+++ b/include/linux/pci.h\n@@ -1915,6 +1915,7 @@ int pci_disable_link_state_locked(struct pci_dev *pdev, int state);\n int pci_enable_link_state(struct pci_dev *pdev, int state);\n int pci_enable_link_state_locked(struct pci_dev *pdev, int state);\n void pcie_no_aspm(void);\n+void pcie_aspm_policy_config_init(void);\n bool pcie_aspm_support_enabled(void);\n bool pcie_aspm_enabled(struct pci_dev *pdev);\n #else\n","prefixes":["RFC","3/4"]}