There is a new feature added from stable kernel
3fa98d338296 ("PCI / PM: Allow runtime PM without callback functions")
and this feature lead to the backport-iwlwifi dkms driver fails to resume
from runtime suspended.
iwlwifi driver fails if pci_finish_runtime_suspend() is called, so check
if runtime_suspend() function is provided before calling this function.
Verified on Dell Precision 5540, wifi keeps working even after S3 test.
Low. pci_finish_runtime_suspend() puts the PCI device into a low power
state, it doesn't hurt if we don't call it, and it passes the 30 times S3
test, so it should be fine to not to call it if runtime_suspend function
is not provided.
AceLan Kao (1):
UBUNTU: SAUCE: PCI/PM: Don't call pci_finish_runtime_suspend()