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| author | Mika Westerberg <mika.westerberg@linux.intel.com> | 2016-06-02 11:17:12 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-06-13 22:57:36 +0300 |
| commit | 9d26d3a8f1b0c442339a235f9508bdad8af91043 (patch) | |
| tree | fda7bf01c07d954d9dceb2a0f1c7a9beba74a67e /include/linux/pci.h | |
| parent | 43f7f88b9362e1f26603b45932069bbd6e15a1e1 (diff) | |
| download | linux-9d26d3a8f1b0c442339a235f9508bdad8af91043.tar.xz | |
PCI: Put PCIe ports into D3 during suspend
Currently the Linux PCI core does not touch power state of PCI bridges and
PCIe ports when system suspend is entered. Leaving them in D0 consumes
power unnecessarily and may prevent the CPU from entering deeper C-states.
With recent PCIe hardware we can power down the ports to save power given
that we take into account few restrictions:
- The PCIe port hardware is recent enough, starting from 2015.
- Devices connected to PCIe ports are effectively in D3cold once the port
is transitioned to D3 (the config space is not accessible anymore and
the link may be powered down).
- Devices behind the PCIe port need to be allowed to transition to D3cold
and back. There is a way both drivers and userspace can forbid this.
- If the device behind the PCIe port is capable of waking the system it
needs to be able to do so from D3cold.
This patch adds a new flag to struct pci_device called 'bridge_d3'. This
flag is set and cleared by the PCI core whenever there is a change in power
management state of any of the devices behind the PCIe port. When system
later on is suspended we only need to check this flag and if it is true
transition the port to D3 otherwise we leave it in D0.
Also provide override mechanism via command line parameter
"pcie_port_pm=[off|force]" that can be used to disable or enable the
feature regardless of the BIOS manufacturing date.
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/linux/pci.h')
| -rw-r--r-- | include/linux/pci.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h index 8d748345b158..8597b423cb63 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -294,6 +294,7 @@ struct pci_dev { unsigned int d2_support:1; /* Low power state D2 is supported */ unsigned int no_d1d2:1; /* D1 and D2 are forbidden */ unsigned int no_d3cold:1; /* D3cold is forbidden */ + unsigned int bridge_d3:1; /* Allow D3 for bridge */ unsigned int d3cold_allowed:1; /* D3cold is allowed by user */ unsigned int mmio_always_on:1; /* disallow turning off io/mem decoding during bar sizing */ @@ -1083,6 +1084,8 @@ int pci_back_from_sleep(struct pci_dev *dev); bool pci_dev_run_wake(struct pci_dev *dev); bool pci_check_pme_status(struct pci_dev *dev); void pci_pme_wakeup_bus(struct pci_bus *bus); +void pci_d3cold_enable(struct pci_dev *dev); +void pci_d3cold_disable(struct pci_dev *dev); static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable) |