diff options
Diffstat (limited to 'drivers/pci/pcie/aspm.c')
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index d320df6375a2..403a44374ed5 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -714,19 +714,12 @@ void pcie_aspm_powersave_config_link(struct pci_dev *pdev) up_read(&pci_bus_sem); } -/* - * pci_disable_link_state - disable pci device's link state, so the link will - * never enter specific states - */ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem, bool force) { struct pci_dev *parent = pdev->bus->self; struct pcie_link_state *link; - if (aspm_disabled && !force) - return; - if (!pci_is_pcie(pdev)) return; @@ -736,6 +729,19 @@ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem, if (!parent || !parent->link_state) return; + /* + * A driver requested that ASPM be disabled on this device, but + * if we don't have permission to manage ASPM (e.g., on ACPI + * systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and + * the _OSC method), we can't honor that request. Windows has + * a similar mechanism using "PciASPMOptOut", which is also + * ignored in this situation. + */ + if (aspm_disabled && !force) { + dev_warn(&pdev->dev, "can't disable ASPM; OS doesn't have ASPM control\n"); + return; + } + if (sem) down_read(&pci_bus_sem); mutex_lock(&aspm_lock); @@ -761,6 +767,15 @@ void pci_disable_link_state_locked(struct pci_dev *pdev, int state) } EXPORT_SYMBOL(pci_disable_link_state_locked); +/** + * pci_disable_link_state - Disable device's link state, so the link will + * never enter specific states. Note that if the BIOS didn't grant ASPM + * control to the OS, this does nothing because we can't touch the LNKCTL + * register. + * + * @pdev: PCI device + * @state: ASPM link state to disable + */ void pci_disable_link_state(struct pci_dev *pdev, int state) { __pci_disable_link_state(pdev, state, true, false); |