PCI/PM: Print config space of devices before suspend

When resuming from hibernation (S4, also known as "suspend to disk") on a VM, we have seen invalid config space, e.g., serial 0000:00:16.3: restoring config space at offset 0x14 (was 0x9104e000, writing 0xffffffff) To help debug problems like this, log the config space being saved before suspend, similar to the log in pci_restore_config_dword() when resuming. Link: https://lore.kernel.org/r/[email protected] [bhelgaas: commit log] Signed-off-by: Chen Yu <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]> Cc: Len Brown <[email protected]>
berg · Jan 13, 2020 · 47b802d · 47b802d
1 parent e42617b
commit 47b802d
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
@@ -1372,8 +1372,11 @@ int pci_save_state(struct pci_dev *dev)
 {
 	int i;
 	/* XXX: 100% dword access ok here? */
-	for (i = 0; i < 16; i++)
+	for (i = 0; i < 16; i++) {
 		pci_read_config_dword(dev, i * 4, &dev->saved_config_space[i]);
+		pci_dbg(dev, "saving config space at offset %#x (reading %#x)\n",
+			i * 4, dev->saved_config_space[i]);
+	}
 	dev->state_saved = true;
 
 	i = pci_save_pcie_state(dev);