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path: root/drivers/pci/pcie/aspm.c
AgeCommit message (Collapse)Author
2008-07-28PCI: add an option to allow ASPM enabled forciblyShaohua Li
A new option, pcie_aspm=force, will force ASPM to be enabled, even on system with PCIe 1.0 devices. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-07-28PCI: disable ASPM on pre-1.1 PCIe devicesShaohua Li
Disable ASPM on pre-1.1 PCIe devices, as many of them don't implement it correctly. Tested-by: Jack Howarth <howarth@bromo.msbb.uc.edu> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-07-28PCI: disable ASPM per ACPI FADT settingShaohua Li
The ACPI FADT table includes an ASPM control bit. If the bit is set, do not enable ASPM since it may indicate that the platform doesn't actually support the feature. Tested-by: Jack Howarth <howarth@bromo.msbb.uc.edu> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-21PCI: don't enable ASPM on devices with mixed PCIe/PCI functionsShaohua Li
The Slot 03:00.* of JMicron controller has two functions, but one is PCIE endpoint the other isn't PCIE device, very strange. PCIE spec defines all functions should have the same config for ASPM, so disable ASPM for the whole slot in this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-04-20PCI: add PCI Express ASPM supportShaohua Li
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 <shaohua.li@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-02Revert "PCI: PCIE ASPM support"Greg Kroah-Hartman
This reverts commit 6c723d5bd89f03fc3ef627d50f89ade054d2ee3b. It caused build errors on non-x86 platforms, config file confusion, and even some boot errors on some x86-64 boxes. All around, not quite ready for prime-time :( Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-01PCI: PCIE ASPM supportShaohua Li
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>