[PATCH] pci: fix kexec with power state D3

[Yinghai Lu <yinghai@kernel.org>]

Impact: second kernel by kexec will have some pci devices working

Found one system with 82575EB, in the kernel that is kexeced, probe igb
failed with -2.

it looks like the same behavior happened on forcedeth.
try to check system_state to make sure if put it on D3

Jesse Brandeburg said that we should do that check in core code instead of
every device driver.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 drivers/pci/pci.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -593,6 +593,14 @@ int pci_set_power_state(struct pci_dev *
 	if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
 		return 0;
 
+	/*
+	 * Apparently it is not possible to reinitialise from D3 hot,
+	 * only put the device into D3 if we really go for poweroff.
+	 */
+	if (system_state != SYSTEM_POWER_OFF &&
+	    (state == PCI_D3hot || state == PCI_D3cold))
+		return 0;
+
 	error = pci_raw_set_power_state(dev, state, true);
 
 	if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
@@ -1124,6 +1132,15 @@ int pci_enable_wake(struct pci_dev *dev,
 	int error = 0;
 	bool pme_done = false;
 
+	/*
+	 * Apparently it is not possible to reinitialise from D3 hot,
+	 * only put the device into D3 if we really go for poweroff.
+	 * we only need to enable wake when we are going to power off
+	 */
+	if (enable && system_state != SYSTEM_POWER_OFF &&
+	    (state == PCI_D3hot || state == PCI_D3cold))
+		return 0;
+
 	if (enable && !device_may_wakeup(&dev->dev))
 		return -EINVAL;