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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/remove.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/remove.c')
-rw-r--r--drivers/pci/remove.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 430281b2e921..05c9ad2a7f8b 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -1,5 +1,6 @@
1#include <linux/pci.h> 1#include <linux/pci.h>
2#include <linux/module.h> 2#include <linux/module.h>
3#include <linux/aspm.h>
3#include "pci.h" 4#include "pci.h"
4 5
5static void pci_free_resources(struct pci_dev *dev) 6static void pci_free_resources(struct pci_dev *dev)
@@ -30,6 +31,9 @@ static void pci_stop_dev(struct pci_dev *dev)
30 dev->global_list.next = dev->global_list.prev = NULL; 31 dev->global_list.next = dev->global_list.prev = NULL;
31 up_write(&pci_bus_sem); 32 up_write(&pci_bus_sem);
32 } 33 }
34
35 if (dev->bus->self)
36 pcie_aspm_exit_link_state(dev);
33} 37}
34 38
35static void pci_destroy_dev(struct pci_dev *dev) 39static void pci_destroy_dev(struct pci_dev *dev)