Hi, On Thu, Aug 24, 2023 at 12:46:43PM +0800, Kai-Heng Feng wrote: > In addition to nearest upstream bridge, driver may want to know if the > entire hierarchy can be powered off to perform different action. > > So walk higher up the hierarchy to find out if any device has valid > _PR3. I'm not entirely sure this is good idea. The drivers should expect that the power will be turned off pretty soon after device enters D3hot. Also _PR3 is not PCI concept it's ACPI concept so API like this would only work on systems with ACPI.
