Problems have been reported on AMD laptops with suspend/resume
where particular root ports are put into D3 and then the system is unable
to resume properly.
The issue boils down to the currently selected kernel policy for root port
behavior at suspend time:
0) If the machine is from 2015 or later
1) If a PCIe root port is power manageable by the platform then platform
will be used to determine the power state of the root port at suspend.
2) If the PCIe root is not power manageable by the platform then the kernel
will check if it was configured to wakeup.
3) If it was, then it will be put into the deepest state that supports
wakeup from PME.
4) If it wasn't, then it will be put into D3hot.
This patch adjusts it so that device constraints for low power idle are
considered if the device is not power manageable by the platform.
Mario Limonciello (3):
ACPI: Add comments to clarify some #ifdef statements
ACPI: x86: s2idle: Adjust constraints logic building
PCI/ACPI: Use device constraints to decide PCI target state fallback
policy
drivers/acpi/x86/s2idle.c | 71 ++++++++++++++++++++++++++-------------
drivers/pci/pci-acpi.c | 22 ++++++++++++
drivers/pci/pci.c | 14 ++++++++
drivers/pci/pci.h | 5 +++
include/linux/acpi.h | 14 +++++---
5 files changed, 99 insertions(+), 27 deletions(-)
--
2.34.1
