pci: Expose PME support by power stateHEADmain

The presence of the PCI power management capability does not imply that
a function can signal PME# from every power state.  Drivers which
advertise wake based only on pci_has_pm() can consequently expose wake
modes that cannot work.

Add pci_has_pme() to query the PME_Support bitmap for a specific state.
Use it to implement LinuxKPI pci_pme_capable(), removing its duplicate
PME_Support decoder.

Validated the helper against PCI PMC capability values from 82571EB,
82573L, 82579LM, I210, I225, and I226-V controllers.  The 82571 and
82573 reported PMC 0xc822, while the I226-V reported 0xc823.  In both
values, bits 15, 14, and 11 advertise PME from D3cold, D3hot, and D0;
the low-bit difference is only the PM capability version.

MFC after:	2 weeks
Sponsored by:	BBOX.io

0 files changed, 0 insertions, 0 deletions