v2 -> v1: . Kept the logic in pci_raw_set_power_state . Changed the ASPM enabling logic . Modified the text that describes the problem 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had a chance to veto it) that pci_enable_device() will result in re-configuring ASPM when aspm_policy is POWERSAVE is no longer valid.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. This makes the equality check (below) become true, so pcie_aspm_pm_state_change() never gets called. ./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; So OSPM doesnn't configure the PCIe links for ASPM. The patch below does the following: At the end of each Root Bridge scan make a call to configure ASPM when the ASPM policy is set to "powersave" mode. Note that if a previous pass had completed the configuration for all devices under that Bridge then the configuration will not take place again because pcie_config_aspm_link() checks to see if the link is already in the requested state. We won't reconfigure ASPM when _OSC control is not granted. In fact, we will disable ASPM in that situation. This is to protect systems with a buggy BIOS that did not set the FADT bit even though the underlying HW can't do ASPM. To turn "on" ASPM the minimum the BIOS needs to do: 1. Clear the ACPI FADT "ASPM Controls" bit. 2. Support _OSC appropriately Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@xxxxxx> Cc: Rafael J. Wysocki <rjw@xxxxxxx> Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 8524939..c0655aa 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -32,6 +32,7 @@ #include <linux/pm_runtime.h> #include <linux/pci.h> #include <linux/pci-acpi.h> +#include <linux/pci-aspm.h> #include <linux/acpi.h> #include <linux/slab.h> #include <acpi/acpi_bus.h> @@ -591,12 +592,22 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) status = acpi_pci_osc_control_set(device->handle, &flags, OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL); - if (ACPI_SUCCESS(status)) + + if (ACPI_SUCCESS(status)) { dev_info(root->bus->bridge, "ACPI _OSC control (0x%02x) granted\n", flags); - else + /* + * When aspm_policy is POWERSAVE, this + * call ensures that ASPM is configured. + */ + pcie_aspm_reconfig_link(root->bus->self); + } else { dev_dbg(root->bus->bridge, "ACPI _OSC request failed (code %d)\n", status); + printk(KERN_INFO "Unable to assume _OSC PCIe control." + " Disabling ASPM.\n"); + pcie_no_aspm(); + } } pci_acpi_add_bus_pm_notifier(device, root->bus); diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 3188cd9..1316745 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -742,6 +742,29 @@ void pci_disable_link_state(struct pci_dev *pdev, int state) } EXPORT_SYMBOL(pci_disable_link_state); +void pcie_aspm_reconfig_link(struct pci_dev *pdev) +{ + struct pcie_link_state *link = NULL; + + if (aspm_disabled) + return; + if (aspm_policy != POLICY_POWERSAVE) + return; + + down_read(&pci_bus_sem); + mutex_lock(&aspm_lock); + + if (list_empty(&link_list)) + goto out; + list_for_each_entry(link, &link_list, sibling) { + pcie_config_aspm_link(link, policy_to_aspm_state(link)); + pcie_set_clkpm(link, policy_to_clkpm_state(link)); + } +out: + mutex_unlock(&aspm_lock); + up_read(&pci_bus_sem); +} + static int pcie_aspm_set_policy(const char *val, struct kernel_param *kp) { int i; diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 5130d0d..595654a 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -15,7 +15,6 @@ #include <linux/slab.h> #include <linux/pcieport_if.h> #include <linux/aer.h> -#include <linux/pci-aspm.h> #include "../pci.h" #include "portdrv.h" @@ -356,10 +355,8 @@ int pcie_port_device_register(struct pci_dev *dev) /* Get and check PCI Express port services */ capabilities = get_port_device_capability(dev); - if (!capabilities) { - pcie_no_aspm(); + if (!capabilities) return 0; - } pci_set_master(dev); /* diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h index ce68105..216b196 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_reconfig_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_reconfig_link(struct pci_dev *pdev) +{ +} static inline void pci_disable_link_state(struct pci_dev *pdev, int state) { } -- 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
