Friendly reminder. Thanks. David On Fri, 2020-06-12 at 13:48 -0700, David E. Box wrote: > This patch set implements a solution for a BIOS hack used on some > currently > shipping Intel systems to address issues with power management policy > decisions concerning PCIe NVMe drives. Some newer Intel platforms, > like > some Comet Lake systems, require that PCIe devices use D3 when doing > suspend-to-idle in order to allow the platform to realize maximum > power > savings. This is particularly needed to support ATX power supply > shutdown > on desktop systems. In order to ensure this happens for root ports > with > storage devices, Microsoft apparently created this ACPI _DSD property > as a > way to override their driver policy. To my knowledge this property > has not > been discussed with the NVME specification body. > > Though the solution is not ideal, it addresses a problem that also > affects > Linux since the NVMe driver's default policy of using NVMe APST > during > suspend-to-idle would lead to higher power consumption for these > platforms. > > Patch 1 provides a symbol in the PCI/ACPI layer to read the property. > Patch 2 uses the symbol in the NVMe driver to select D3 as a quirk if > set. > > Changes from V2: > - Export the pci_acpi_storage_d3 function for use by drivers as > needed instead of modifying the pci header. > - Add missing put on acpi device handle. > - Add 'noacpi' module parameter to allow undoing this change. > - Add info message that this is a platform quirk. > > 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 | 14 ++++++++++ > drivers/pci/pci-acpi.c | 59 > +++++++++++++++++++++++++++++++++++++++++ > include/linux/pci.h | 2 ++ > 4 files changed, 78 insertions(+) >
