From 7d715a6c1ae5785d00fb9a876b5abdfc43abc44b Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 25 Feb 2008 09:46:41 +0800 Subject: PCI: add PCI Express ASPM support PCI Express ASPM defines a protocol for PCI Express components in the D0 state to reduce Link power by placing their Links into a low power state and instructing the other end of the Link to do likewise. This capability allows hardware-autonomous, dynamic Link power reduction beyond what is achievable by software-only controlled power management. However, The device should be configured by software appropriately. Enabling ASPM will save power, but will introduce device latency. This patch adds ASPM support in Linux. It introduces a global policy for ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control it. The interface can be used as a boot option too. Currently we have below setting: -default, BIOS default setting -powersave, highest power saving mode, enable all available ASPM state and clock power management -performance, highest performance, disable ASPM and clock power management By default, the 'default' policy is used currently. In my test, power difference between powersave mode and performance mode is about 1.3w in a system with 3 PCIE links. Note: some devices might not work well with aspm, either because chipset issue or device issue. The patch provide API (pci_disable_link_state), driver can disable ASPM for specific device. Signed-off-by: Shaohua Li Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index a4445b7210bf..f331feb4eb8d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -18,6 +18,7 @@ #include #include #include +#include #include /* isa_dma_bridge_buggy */ #include "pci.h" @@ -501,6 +502,9 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state) if (need_restore) pci_restore_bars(dev); + if (dev->bus->self) + pcie_aspm_pm_state_change(dev->bus->self); + return 0; } -- cgit v1.2.1 From 66bef8c059015ba2b36bb5759080336feb01e680 Mon Sep 17 00:00:00 2001 From: Harvey Harrison Date: Mon, 3 Mar 2008 19:09:46 -0800 Subject: PCI: replace remaining __FUNCTION__ occurrences __FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index f331feb4eb8d..e4548ab2a93c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -425,7 +425,7 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state) */ if (state != PCI_D0 && dev->current_state > state) { printk(KERN_ERR "%s(): %s: state=%d, current state=%d\n", - __FUNCTION__, pci_name(dev), state, dev->current_state); + __func__, pci_name(dev), state, dev->current_state); return -EINVAL; } else if (dev->current_state == state) return 0; /* we're already there */ -- cgit v1.2.1