PCI PM: Restore standard config registers of all devices early

There is a problem in our handling of suspend-resume of PCI devices that
many of them have their standard config registers restored with
interrupts enabled and they are put into the full power state with
interrupts enabled as well.  This may lead to the following scenario:
  * an interrupt vector is shared between two or more devices
  * one device is resumed earlier and generates an interrupt
  * the interrupt handler of another device tries to handle it and
    attempts to access the device the config space of which hasn't been
    restored yet and/or which still is in a low power state
  * the system crashes as a result

To prevent this from happening we should restore the standard
configuration registers of all devices with interrupts disabled and we
should put them into the D0 power state right after that.
Unfortunately, this cannot be done using the existing
pci_set_power_state(), because it can sleep.  Also, to do it we have to
make sure that the config spaces of all devices were actually saved
during suspend.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1351bb4..26ddf78 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -49,6 +49,12 @@ extern void pci_disable_enabled_device(struct pci_dev *dev);
 extern void pci_pm_init(struct pci_dev *dev);
 extern void platform_pci_wakeup_init(struct pci_dev *dev);
 extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);
+extern int pci_restore_standard_config(struct pci_dev *dev);
+
+static inline bool pci_is_bridge(struct pci_dev *pci_dev)
+{
+	return !!(pci_dev->subordinate);
+}
 
 extern int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
 extern int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);