linux/drivers/pci
Rafael J. Wysocki 4514d991d9 PCI: PM: Do not read power state in pci_enable_device_flags()
It should not be necessary to update the current_state field of
struct pci_dev in pci_enable_device_flags() before calling
do_pci_enable_device() for the device, because none of the
code between that point and the pci_set_power_state() call in
do_pci_enable_device() invoked later depends on it.

Moreover, doing that is actively harmful in some cases.  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 it is better to leave the current_state value
as is until it is changed to PCI_D0 by do_pci_enable_device() as
appropriate.  However, the power state of the device is not changed
to PCI_D0 if it is already enabled when pci_enable_device_flags()
gets called for it, so update its current_state in that case, but
use pci_update_current_state() covering platform PM too for that.

Link: https://lore.kernel.org/lkml/20210314000439.3138941-1-luzmaximilian@gmail.com/
Reported-by: Maximilian Luz <luzmaximilian@gmail.com>
Tested-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2021-03-24 16:39:23 +01:00
..
controller pci-v5.12-changes 2021-02-25 09:56:08 -08:00
endpoint PCI: endpoint: Add EP function driver to provide NTB functionality 2021-02-23 14:12:28 -06:00
hotplug powerpc fixes for 5.12 #4 2021-03-21 10:57:35 -07:00
pcie pci-v5.12-changes 2021-02-25 09:56:08 -08:00
switch PCI: switchtec: Add missing __iomem tag to fix sparse warnings 2020-07-31 11:23:45 -05:00
access.c Merge branch 'pci/misc' 2020-08-05 18:24:16 -05:00
ats.c Merge branch 'pci/doc' 2020-08-05 18:24:22 -05:00
bus.c PCI: Add device even if driver attach failed 2020-07-07 17:33:41 -05:00
ecam.c PCI: Unify ECAM constants in native PCI Express drivers 2020-12-10 14:55:49 -06:00
host-bridge.c
iov.c PCI/IOV: Mark VFs as not implementing PCI_COMMAND_MEMORY 2020-09-21 14:42:11 -06:00
irq.c PCI: Remove unused pci_lost_interrupt() 2020-07-29 14:25:18 -05:00
Kconfig pci-v5.10-changes 2020-10-22 12:41:00 -07:00
Makefile PCI: Apply CONFIG_PCI_DEBUG to entire drivers/pci hierarchy 2021-02-09 15:10:20 -06:00
mmap.c
msi.c PCI/MSI: Set device flag indicating only 32-bit MSI support 2020-12-04 12:17:04 -06:00
of.c PCI: of: Warn if non-prefetchable memory aperture size is > 32-bit 2020-11-18 16:16:38 +00:00
p2pdma.c RDMA 5.11 pull request 2020-12-16 13:42:26 -08:00
pci-acpi.c pci-v5.11-changes 2020-12-15 16:49:59 -08:00
pci-bridge-emul.c PCI: pci-bridge-emul: Fix array overruns, improve safety 2021-02-17 17:25:31 -06:00
pci-bridge-emul.h
pci-driver.c Merge branch 'pci/misc' 2020-12-15 15:11:08 -06:00
pci-label.c PCI: Replace http:// links with https:// 2020-06-30 13:05:09 -05:00
pci-mid.c
pci-pf-stub.c PCI/IOV: Simplify pci-pf-stub with module_pci_driver() 2020-09-17 12:40:20 -05:00
pci-stub.c
pci-sysfs.c PCI: Revoke mappings like devmem 2021-02-11 15:59:19 +01:00
pci.c PCI: PM: Do not read power state in pci_enable_device_flags() 2021-03-24 16:39:23 +01:00
pci.h drm pull for 5.12-rc1 2021-02-21 14:44:44 -08:00
probe.c Merge branch 'pci/msi' 2020-12-15 15:11:08 -06:00
proc.c PCI: Revoke mappings like devmem 2021-02-11 15:59:19 +01:00
quirks.c Merge branch 'remotes/lorenzo/pci/dwc' 2020-12-15 15:11:11 -06:00
remove.c
rom.c
search.c PCI: Remove WARN_ON(in_interrupt()) 2021-02-10 16:46:29 -06:00
setup-bus.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
setup-irq.c
setup-res.c PCI: Decline to resize resources if boot config must be preserved 2021-01-12 16:39:52 -06:00
slot.c Merge branch 'pci/misc' 2020-12-15 15:11:08 -06:00
syscall.c PCI: Align checking of syscall user config accessors 2021-01-27 10:41:59 -06:00
vc.c PCI: Fix kerneldoc warnings 2020-08-05 18:23:14 -05:00
vpd.c
xen-pcifront.c Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF} 2021-03-10 16:39:29 -06:00