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authorShaohua Li <shaohua.li@intel.com>2008-01-23 21:21:57 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2008-02-01 18:04:30 -0500
commit6c723d5bd89f03fc3ef627d50f89ade054d2ee3b (patch)
tree45fcf8a380b48ddf686456ff65a2234c23c05504 /drivers/pci/pci-sysfs.c
parent5c796ae7a7ebe56967ed9b9963d7c16d733635ff (diff)
PCI: PCIE 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. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/pci/pci-sysfs.c')
-rw-r--r--drivers/pci/pci-sysfs.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 7d1877341aad..d05c1b252386 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -21,6 +21,7 @@
21#include <linux/topology.h> 21#include <linux/topology.h>
22#include <linux/mm.h> 22#include <linux/mm.h>
23#include <linux/capability.h> 23#include <linux/capability.h>
24#include <linux/aspm.h>
24#include "pci.h" 25#include "pci.h"
25 26
26static int sysfs_initialized; /* = 0 */ 27static int sysfs_initialized; /* = 0 */
@@ -650,6 +651,8 @@ int __must_check pci_create_sysfs_dev_files (struct pci_dev *pdev)
650 if (pcibios_add_platform_entries(pdev)) 651 if (pcibios_add_platform_entries(pdev))
651 goto err_rom_file; 652 goto err_rom_file;
652 653
654 pcie_aspm_create_sysfs_dev_files(pdev);
655
653 return 0; 656 return 0;
654 657
655err_rom_file: 658err_rom_file:
@@ -679,6 +682,8 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
679 if (!sysfs_initialized) 682 if (!sysfs_initialized)
680 return; 683 return;
681 684
685 pcie_aspm_remove_sysfs_dev_files(pdev);
686
682 if (pdev->cfg_size < 4096) 687 if (pdev->cfg_size < 4096)
683 sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr); 688 sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
684 else 689 else