On Fri, Apr 29, 2016 at 11:51:55AM +0300, Mika Westerberg wrote: > 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. > > Previous versions of the patches can be found below: > > v1: http://www.spinics.net/lists/linux-pci/msg49313.html > v2: http://www.spinics.net/lists/linux-pci/msg50167.html > v3: http://www.spinics.net/lists/linux-pci/msg50345.html > v4: http://www.spinics.net/lists/linux-pci/msg50665.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 two new functions pci_bridge_d3_device_changed/removed(). These > are used to set and clear 'bridge_d3' whenever there is a change in device > power management policy (or if the device is removed). For example when > userspace forbids the device to enter D3cold pci_bridge_d3_device_changed() > will clear 'bridge_d3' of the upstream bridge. > > 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 v4: > > - Use "Put PCIe ports into D3" instead of "move" in subject and comments. > > - Add new helper function pci_power_manageable() and use it to check if > the port can be suspended instead of open-coding it everytime. > > - Changed pci_dev_check_d3cold() to follow what Rafael suggested. > > - Dropped call to pm_runtime_mark_last_busy() in pcie_port_runtime_resume() > as PM core does that automatically when the function returns 0. > > - Added ACKs from Rafael. > > Changes to v3: > > - Make 'no_d3cold' persist for pci_dev. Once this is set through > pci_d3cold_enable/disable(), it will persist unless changed again using > the same functions. Those also handle setting and clearing 'bridge_d3' > as necessary. > > - Add kernel command line parameter "pcie_port_pm=off|force" that can > be used to forcibly disable/enable the feature. > > - Use runtime PM autosuspend instead of scheduling runtime suspend > manually > > - Allow runtime PM always except when we are dealing with a hotplug > bridge. Actual checking whether the port can be suspended is done in > ->idle() and ->runtime_suspend() hooks based on 'bridge_d3'. > > Changes to v2: > > - Renamed and split pci_enable_d3cold() into two functions > pci_d3cold_enable()/disable(). > > - Renamed pci_bridge_pm_update() into two functions > pci_bridge_d3_device_changed() and pci_bridge_d3_device_removed() that > should match better what they are doing. > > - Propagate ->bridge_d3 change to upstream bridges in > pci_bridge_d3_update(). > > - Removed pci_can_suspend() in favor of doing ->bridge_d3 check directly > in pci_pm_suspend_noirq(). > > - Extend runtime PM enabling for ports that are using native PCIe > hotplug. > > - Call pm_runtime_no_callbacks() for PCIe port service devices (the are > handled by the parent device). > > Changes to v1: > > - 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. > > Mika Westerberg (4): > PCI: No need to set d3cold_allowed to PCIe ports > PCI: Put PCIe ports into D3 during suspend > ACPI / hotplug / PCI: Runtime resume bridge before rescan > PCI: Add runtime PM support for PCIe ports > > Documentation/kernel-parameters.txt | 4 + > drivers/pci/bus.c | 1 + > drivers/pci/hotplug/acpiphp_glue.c | 8 +- > drivers/pci/pci-driver.c | 5 +- > drivers/pci/pci-sysfs.c | 5 ++ > drivers/pci/pci.c | 175 ++++++++++++++++++++++++++++++++++++ > drivers/pci/pci.h | 11 +++ > drivers/pci/pcie/portdrv_core.c | 2 + > drivers/pci/pcie/portdrv_pci.c | 51 ++++++++++- > drivers/pci/remove.c | 2 + > drivers/usb/host/xhci-pci.c | 2 +- > include/linux/pci.h | 3 + > 12 files changed, 259 insertions(+), 10 deletions(-) Applied with Lukas' Tested-by and Rafael's Acks to pci/pm for v4.7, thanks Mika! -- 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
