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Wysocki" Cc: "David E . Box" , Lukas Wunner , Manivannan Sadhasivam , Len Brown , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Falcon Subject: [RFC PATCH 2/4] pcie/aspm: Enable all power-saving states during link state initialization Date: Wed, 29 Apr 2026 13:06:44 -0500 Message-ID: <20260429180647.197072-3-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-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Setting powersave and powersupersave states at ASPM link state initialization allows for a simpler and more maintainable enabling flow that presumes all advertised power states work. Restrict this behavior to systems with a BIOS release during or after 2025. Suggested-by: David E. Box Signed-off-by: Thomas Falcon --- drivers/pci/pcie/aspm.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index cd23c1462502..84d49aa8a5ba 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -24,6 +24,7 @@ #include #include #include +#include #include "../pci.h" @@ -1057,6 +1058,23 @@ static void free_link_state(struct pcie_link_state *link) kfree(link); } +static int pcie_aspm_legacy_config_check(void) +{ + static bool legacy_aspm_config; + static bool checked; + + if (checked) + return legacy_aspm_config; + if (dmi_get_bios_year() < 2025) + legacy_aspm_config = true; + + pr_info("ASPM configuration is determined at %s time\n", + legacy_aspm_config ? "build" : "boot"); + checked = true; + + return legacy_aspm_config; +} + static int pcie_aspm_sanity_check(struct pci_dev *pdev) { struct pci_dev *child; @@ -1196,8 +1214,9 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * the BIOS's expectation, we'll do so once pci_enable_device() is * called. */ - if (aspm_policy != POLICY_POWERSAVE && - aspm_policy != POLICY_POWER_SUPERSAVE) { + if (!pcie_aspm_legacy_config_check() || + (aspm_policy != POLICY_POWERSAVE && + aspm_policy != POLICY_POWER_SUPERSAVE)) { pcie_config_aspm_path(link); pcie_set_clkpm(link, policy_to_clkpm_state(link)); } @@ -1379,8 +1398,9 @@ void pcie_aspm_powersave_config_link(struct pci_dev *pdev) if (aspm_disabled || !link) return; - if (aspm_policy != POLICY_POWERSAVE && - aspm_policy != POLICY_POWER_SUPERSAVE) + if (!pcie_aspm_legacy_config_check() || + (aspm_policy != POLICY_POWERSAVE && + aspm_policy != POLICY_POWER_SUPERSAVE)) return; down_read(&pci_bus_sem); -- 2.43.0