NVMe storage power management during suspend-to-idle, particularly on
laptops, has been inconsistent with some devices working with D3 while
others must rely on NVMe APST in order for power savings to be realized.
Currently the default is to use APST unless quirked to do otherwise.
However newer platforms, like Intel Comet Lake systems, may require NVMe
drives to use D3 in order for the PCIe ports to be properly power managed.
To make it easier for drivers to choose, these platforms may supply a
special "StorageD3Enable" _DSD property under the root port that the device
is attached to. If supplied, the driver must use D3 in order for the
platform to realize the deepest power savings in suspend-to-idle.
The first patch adds the new _DSD GUID and fowards the property through the
pci/acpi layer to the pci device.
The second patch adds support for the property to the nvme driver.
David E. Box (2):
pci: Add ACPI StorageD3Enable _DSD support
drivers/nvme: Add support for ACPI StorageD3Enable property
drivers/acpi/property.c | 3 +++
drivers/nvme/host/pci.c | 7 ++++++
drivers/pci/pci-acpi.c | 47 +++++++++++++++++++++++++++++++++++++++++
drivers/pci/pci.c | 6 ++++++
drivers/pci/pci.h | 4 ++++
include/linux/pci.h | 1 +
6 files changed, 68 insertions(+)
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2.20.1
