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Subject[patch 24/30] PCI PM: Follow PCI_PM_CTRL_NO_SOFT_RESET during transitions from D3
2.6.27-stable review patch.  If anyone has any objections, please let us know.


From: Rafael J. Wysocki <>

commit f62795f1e892ca9269849fa83de97621da7e02c0 upstream.

According to the PCI PM specification (PCI Bus Power Management
Interface Specification, Rev. 1.2, Section 5.4.1) we are supposed to
reinitialize devices that have PCI_PM_CTRL_NO_SOFT_RESET clear during
all transitions from PCI_D3hot to PCI_D0, but we only do it if the
device's current_state field is equal to PCI_UNKNOWN.

This may lead to problems if a device with PCI_PM_CTRL_NO_SOFT_RESET
unset is put into PCI_D3hot at run time by its driver and
pci_set_power_state() is used to put it back into PCI_D0, because in
that case the device will remain uninitialized after
pci_set_power_state() has returned. Prevent that from happening by
modifying pci_raw_set_power_state() to reinitialize devices with
PCI_PM_CTRL_NO_SOFT_RESET unset during all transitions from D3 to D0.

Signed-off-by: Rafael J. Wysocki <>
Signed-off-by: Jesse Barnes <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/pci/pci.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -473,6 +473,8 @@ pci_raw_set_power_state(struct pci_dev *
pmcsr |= state;
+ case PCI_D3hot:
+ case PCI_D3cold:
case PCI_UNKNOWN: /* Boot-up */
if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
&& !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))

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