PCI: Use pci_update_current_state() in pci_enable_device_flags()
authorRafael J. Wysocki <rafael.j.wysocki@intel.com>
Thu, 8 Jul 2021 13:25:06 +0000 (15:25 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 18 Sep 2021 11:40:17 +0000 (13:40 +0200)
commitcc12ab5951aa3a9d0893614120560179db8659a2
tree35195a08f13a0723bb4b5bf18734b630a697b662
parentaad29a00a5983d3ed2d6ca06d2ab63a4f8a61adc
PCI: Use pci_update_current_state() in pci_enable_device_flags()

[ Upstream commit 14858dcc3b3587f4bb5c48e130ee7d68fc2b0a29 ]

Updating the current_state field of struct pci_dev the way it is done
in pci_enable_device_flags() before calling do_pci_enable_device() may
not work.  For example, if the given PCI device depends on an ACPI
power resource whose _STA method initially returns 0 ("off"), but the
config space of the PCI device is accessible and the power state
retrieved from the PCI_PM_CTRL register is D0, the current_state
field in the struct pci_dev representing that device will get out of
sync with the power.state of its ACPI companion object and that will
lead to power management issues going forward.

To avoid such issues, make pci_enable_device_flags() call
pci_update_current_state() which takes ACPI device power management
into account, if present, to retrieve the current power state of the
device.

Link: https://lore.kernel.org/lkml/20210314000439.3138941-1-luzmaximilian@gmail.com/
Reported-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/pci/pci.c