Current Linux PCI core does not do any kind of power management to PCIe ports. This means that we waste energy and consume laptop battery even if the port has nothing connected to. These patches aim to change that to the right direction. The first version of the patches can be found here: http://www.spinics.net/lists/linux-pci/msg49313.html This assumes that recent (starting from 2015) PCIe ports are capable of transition to D3hot/D3cold. We add a new flag to struct pci_dev 'bridge_d3' that is set whenever the PCI core thinks the port can be put to D3. The check in pci_pm_suspend_noirq() is then extended to cover devices where 'bridge_d3' is set. We then add pci_bridge_pm_update() that tries to set/clear 'bridge_d3' whenever power management status of a device is changed. For example when userspace writes to 'd3cold_allowed' sysfs file. For all PCI ports where 'bridge_d3' is set we also enable and unblock runtime PM automatically. Only exception is when the PCIe port claims to support hotplug. More information about that is in the changelog of patch [4/4]. Since this also touches xhci, I'm adding Mathias and Greg to check if the change looks reasonable. Changes to the previous version: - Dropped patch [2/6] as there is no need to use that function from other files anymore. - Dropped patches [5-6/6] in favor of using cut-off date. - Updated changelog of [1/4] to mention where in the PCI core PCI bridge and PCIe ports are skipped from being power managed. - Instead of checking at suspend time if it is possible to transition the port to D3, do it whenever power management status of a device (below a port) is changed or when it is added or removed to the bus. - Added patch [3/4] to runtime resume a bridge when ACPI hotplug event is received. Please review. Mika Westerberg (4): PCI: No need to set d3cold_allowed to PCIe ports PCI: Move PCIe ports to D3 during suspend ACPI / hotplug / PCI: Runtime resume bridge before rescan PCI: Add runtime PM support for PCIe ports drivers/pci/bus.c | 1 + drivers/pci/hotplug/acpiphp_glue.c | 8 ++- drivers/pci/pci-driver.c | 15 +++++- drivers/pci/pci-sysfs.c | 1 + drivers/pci/pci.c | 103 +++++++++++++++++++++++++++++++++++++ drivers/pci/pci.h | 1 + drivers/pci/pcie/portdrv_pci.c | 90 ++++++++++++++++++++++++++++++-- drivers/pci/remove.c | 2 + drivers/usb/host/xhci-pci.c | 2 +- include/linux/pci.h | 2 + 10 files changed, 216 insertions(+), 9 deletions(-) -- 2.8.0.rc3 -- 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
