From: Kai-Heng Feng Date: Tue, 5 May 2020 17:34:21 +0000 (+0800) Subject: PCI/ASPM: Allow ASPM on links to PCIe-to-PCI/PCI-X Bridges X-Git-Tag: v5.8-rc1~115^2~24^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=66ff14e59e8a30690755b08bc3042359703fb07a;p=thirdparty%2Fkernel%2Flinux.git PCI/ASPM: Allow ASPM on links to PCIe-to-PCI/PCI-X Bridges 7d715a6c1ae5 ("PCI: add PCI Express ASPM support") added the ability for Linux to enable ASPM, but for some undocumented reason, it didn't enable ASPM on links where the downstream component is a PCIe-to-PCI/PCI-X Bridge. Remove this exclusion so we can enable ASPM on these links. The Dell OptiPlex 7080 mentioned in the bugzilla has a TI XIO2001 PCIe-to-PCI Bridge. Enabling ASPM on the link leading to it allows the Intel SoC to enter deeper Package C-states, which is a significant power savings. [bhelgaas: commit log] Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207571 Link: https://lore.kernel.org/r/20200505173423.26968-1-kai.heng.feng@canonical.com Signed-off-by: Kai-Heng Feng Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg --- diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 2378ed6925346..b17e5ffd31b14 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -628,16 +628,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) /* Setup initial capable state. Will be updated later */ link->aspm_capable = link->aspm_support; - /* - * If the downstream component has pci bridge function, don't - * do ASPM for now. - */ - list_for_each_entry(child, &linkbus->devices, bus_list) { - if (pci_pcie_type(child) == PCI_EXP_TYPE_PCI_BRIDGE) { - link->aspm_disable = ASPM_STATE_ALL; - break; - } - } /* Get and check endpoint acceptable latencies */ list_for_each_entry(child, &linkbus->devices, bus_list) {