v3 -> v2: Moved ASPM enabling logic to pci_set_power_state() v2 -> v1: Preserved the logic in pci_raw_set_power_state() : Added ASPM enabling logic after scanning Root Bridge : http://marc.info/?l=linux-pci&m=130046996216391&w=2 v1 : http://marc.info/?l=linux-pci&m=130013164703283&w=2 The assumption made in commit 41cd766b065970ff6f6c89dd1cf55fa706c84a3d (PCI: Don't enable aspm before drivers have had a chance to veto it) that pci_enable_device() will result in re-configuring ASPM when aspm_policy is POWERSAVE is no longer valid. This is due to commit 97c145f7c87453cec90e91238fba5fe2c1561b32 (PCI: read current power state at enable time) which resets dev->current_state to D0. Due to this the call to pcie_aspm_pm_state_change() is never made. Note the equality check (below) that returns early: ./drivers/pci/pci.c: pci_raw_set_pci_power_state() 546 /* Check if we're already there */ 547 if (dev->current_state == state) 548 return 0; Therefore OSPM never configures the PCIe links for ASPM to turn them "on". Fix it by configuring ASPM from the pci_enable_device() code path. This also allows a driver such as the e1000e networking driver a chance to disable ASPM (L0s, L1), if need be, prior to enabling the device. A driver may perform this action if the device is known to mis-behave wrt ASPM. Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@xxxxxx> Cc: Rafael J. Wysocki <rjw@xxxxxxx> Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx> --- drivers/pci/pci.c | 6 ++++++ drivers/pci/pcie/aspm.c | 22 ++++++++++++++++++++++ include/linux/pci-aspm.h | 4 ++++ 3 files changed, 32 insertions(+), 0 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b714d78..2472e71 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -740,6 +740,12 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) if (!__pci_complete_power_transition(dev, state)) error = 0; + /* + * When aspm_policy is "powersave" this call ensures + * that ASPM is configured. + */ + if (!error && dev->bus->self) + pcie_aspm_powersave_config_link(dev->bus->self); return error; } diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 3188cd9..e768620 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -707,6 +707,28 @@ void pcie_aspm_pm_state_change(struct pci_dev *pdev) up_read(&pci_bus_sem); } +void pcie_aspm_powersave_config_link(struct pci_dev *pdev) +{ + struct pcie_link_state *link = pdev->link_state; + + if (aspm_disabled || !pci_is_pcie(pdev) || !link) + return; + + if (aspm_policy != POLICY_POWERSAVE) + return; + + if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) && + (pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)) + return; + + down_read(&pci_bus_sem); + mutex_lock(&aspm_lock); + pcie_config_aspm_path(link); + pcie_set_clkpm(link, policy_to_clkpm_state(link)); + mutex_unlock(&aspm_lock); + up_read(&pci_bus_sem); +} + /* * pci_disable_link_state - disable pci device's link state, so the link will * never enter specific states diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h index ce68105..67cb3ae 100644 --- a/include/linux/pci-aspm.h +++ b/include/linux/pci-aspm.h @@ -26,6 +26,7 @@ extern void pcie_aspm_init_link_state(struct pci_dev *pdev); extern void pcie_aspm_exit_link_state(struct pci_dev *pdev); extern void pcie_aspm_pm_state_change(struct pci_dev *pdev); +extern void pcie_aspm_powersave_config_link(struct pci_dev *pdev); extern void pci_disable_link_state(struct pci_dev *pdev, int state); extern void pcie_clear_aspm(void); extern void pcie_no_aspm(void); @@ -39,6 +40,9 @@ static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { } +static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) +{ +} static inline void pci_disable_link_state(struct pci_dev *pdev, int state) { } -- 1.7.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
