[PATCH 0/1][SRU][Bionic] Fix Nvidia fails after switching its mode

[AceLan Kao]

BugLink: https://bugs.launchpad.net/bugs/1778658

[Impact]
Switch Nvidia mode requires rebooting the system. It's because of
losing some of its states while switching mode if runtime PM is enabled.
It's a generic issue that would happen on some other devices, too.
This patch restores devices' config space on runtime resume.

[Test]
Test and verify it on machines with Nvidia discrete graphics.

[Fix]
Fix by saving and restoring config space over a runtime suspend cycle
even if the device is not bound.

[Regression Potential]
Low. It just saves and restores states during suspending and resuming.

Rafael J. Wysocki (1):
  PCI: Restore config space on runtime resume despite being unbound

 drivers/pci/pci-driver.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

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2.17.1