cciss: add small delay when using PCI Power Management to reset for kump

The P600 requires a small delay when changing states. Otherwise we may think
the board did not reset and we bail. This for kdump only and is particular
to the P600.

Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/cciss.c

@@ -4557,6 +4557,13 @@ static int cciss_controller_hard_reset(struct pci_dev *pdev,
 		pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
 		pmcsr |= PCI_D0;
 		pci_write_config_word(pdev, pos + PCI_PM_CTRL, pmcsr);
+
+		/*
+		 * The P600 requires a small delay when changing states.
+		 * Otherwise we may think the board did not reset and we bail.
+		 * This for kdump only and is particular to the P600.
+		 */
+		msleep(500);
 	}
 	return 0;
 }