[patch 091/108] PCI PM: Follow PCI_PM_CTRL_NO_SOFT_RESET during transitions from D3

Greg KH
2009-07-01T01:13:43Z

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2.6.30-stable review patch. If anyone has any objections, please let us know.

------------------

From: Rafael J. Wysocki <rjw@sisk.pl>

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 <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -480,6 +480,8 @@ static int pci_raw_set_power_state(struc
pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
pmcsr |= state;
break;
+ 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))