PCI: check for pci bar restore completion and retry

On some OEM systems, pci_restore_state() is called while FLR has not yet
completed.  As a result, PCI BAR register restore is not successful.  This fix
reads back the restored value and compares it with saved value and re-tries 10
times before giving up.

Signed-off-by: Jean Guyader <jean.guyader@eu.citrix.com>
Signed-off-by: Eric Chanudet <eric.chanudet@citrix.com>
Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 053670e09e2..9c89447e7b2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -959,6 +959,7 @@ void pci_restore_state(struct pci_dev *dev)
 {
         int i;
         u32 val;
+        int tries;
 
         if (!dev->state_saved)
                 return;
@@ -973,12 +974,16 @@ void pci_restore_state(struct pci_dev *dev)
          */
         for (i = 15; i >= 0; i--) {
                 pci_read_config_dword(dev, i * 4, &val);
-                if (val != dev->saved_config_space[i]) {
+                tries = 10;             
+                while (tries && val != dev->saved_config_space[i]) {
                         dev_dbg(&dev->dev, "restoring config "
                                 "space at offset %#x (was %#x, writing %#x)\n",
                                 i, val, (int)dev->saved_config_space[i]);
                         pci_write_config_dword(dev,i * 4,
                                 dev->saved_config_space[i]);
+                        pci_read_config_dword(dev, i * 4, &val);
+                        mdelay(10);
+                        tries--;
                 }
         }
         pci_restore_pcix_state(dev);