PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it
PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it

Some devices have hardware problems related to using ASPM.  Drivers for
these devices use pci_disable_link_state() to prevent their device from
entering L0s or L1.  But on platforms where the OS doesn't have permission
to manage ASPM, pci_disable_link_state() doesn't actually disable ASPM.

Windows has a similar mechanism ("PciASPMOptOut"), and when the OS doesn't
have control of ASPM, it doesn't actually disable ASPM either.

This patch just adds a warning in dmesg about the fact that
pci_disable_link_state() is doing nothing.

Reported-by: Emmanuel Grumbach <db59307858c5dc921a142d8ec4e7e3b0a44d5534@gmail.com>
Reference: 41d150e6dec2ee5855fe09b9cce471d272191e88@mail.gmail.com
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=57331
Signed-off-by: Bjorn Helgaas <f10ec01be0c6b54271af5c550cd257810bdf3268@google.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs