A number of AMD based OEM systems have problems coming out of s2idle, which is rooted in that the NVME device power is cut off during s2idle. That alone is not a bug - the architecture used on Cezanne, Renoir and Picasso expects this. Many of these systems do include the StorageD3Enable property, but it is located in the PCI device itself not in a root port sibling like on Intel. Intel confirmed that this during pre-production it was placed there, and actually for production using the PCI device itself is sufficient. During the course of discussions on the merits of different approaches it was mentioned that although originally introduced for NVME devices, the Microsoft specification makes allusions to non-PCI based ACPI storage devices as well, so a proposal was created to move this into the ACPI subsystem. If at a later time different firmware solutions decide to advertise this functionality, it may make sense to move out of acpi into a more generic location. However both AMD's and Intel's solutions for s2idle also rely upon calling other ACPI drivers and adopting another solution will require coming up with alternatives for those as well. Mario Limonciello (2): nvme: Look for StorageD3Enable on companion ACPI device instead acpi: Move check for _DSD StorageD3Enable property to acpi drivers/acpi/device_pm.c | 24 +++++++++++++++++++ drivers/nvme/host/pci.c | 50 +--------------------------------------- include/linux/acpi.h | 5 ++++ 3 files changed, 30 insertions(+), 49 deletions(-) -- 2.25.1
