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PCI/ASPM: Add sysfs attributes for controlling ASPM link states

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Add sysfs attributes to Endpoints and other Upstream Ports to control ASPM,
Clock PM, and L1 PM Substates.  The new attributes are:

  /sys/devices/pci*/.../link/clkpm
  /sys/devices/pci*/.../link/l0s_aspm
  /sys/devices/pci*/.../link/l1_aspm
  /sys/devices/pci*/.../link/l1_1_aspm
  /sys/devices/pci*/.../link/l1_2_aspm
  /sys/devices/pci*/.../link/l1_1_pcipm
  /sys/devices/pci*/.../link/l1_2_pcipm

An attribute is only visible if both ends of the Link leading to the device
support the state.  Writing y/1/on to the file enables the state; n/0/off
disables it.

These attributes can be used to tune the power/performance tradeoff for
individual devices.

[bhelgaas: commit log, rename directory to "link"]
Link: https://lore.kernel.org/r/b1c83f8a-9bf6-eac5-82d0-cf5b90128fbf@gmail.com
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Heiner Kallweit
2019-10-05 14:07:56 +02:00
committed by Bjorn Helgaas
parent 687aaf386a
commit 72ea91afbf
4 changed files with 169 additions and 0 deletions
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3
drivers/pci/pci-sysfs.c
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@@ -1587,6 +1587,9 @@ static const struct attribute_group *pci_dev_attr_groups[] = {
&pcie_dev_attr_group,
#ifdef CONFIG_PCIEAER
&aer_stats_attr_group,
#endif
#ifdef CONFIG_PCIEASPM
&aspm_ctrl_attr_group,
#endif
NULL,
};