[PATCH v3 7/9] pci: Wake-up devices before save for reset

Alex Williamson
2013-08-01T16:56:01Z

Devices come out of reset in D0. Restoring a device to a different
post-reset state takes more smarts than our simple config space
restore, which can leave devices in an inconsistent state. For
example, if a device is reset in D3, but the restore doesn't
successfully return the device to D3, then the actual state of the
device and dev->current_state are contradictory. Put everything
in D0 going into the reset, then we don't need to do anything
special on the way out.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/pci/pci.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 91f7bc4..3e71887 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3393,6 +3393,13 @@ static void pci_dev_unlock(struct pci_dev *dev)

static void pci_dev_save_and_disable(struct pci_dev *dev)
{
+ /*
+ * Wake-up device prior to save. PM registers default to D0 after
+ * reset and a simple register restore doesn't reliably return
+ * to a non-D0 state anyway.
+ */
+ pci_set_power_state(dev, PCI_D0);
+
pci_save_state(dev);
/*
* both INTx and MSI are disabled after the Interrupt Disable bit