1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6e7dc6f93978..dfa44d3e8eee 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -175,6 +175,16 @@ int xhci_reset(struct xhci_hcd *xhci)
         command |= CMD_RESET;
         writel(command, &xhci->op_regs->command);
 
+        /* Existing Intel xHCI controllers require a delay of 1 mS,
+         * after setting the CMD_RESET bit, and before accessing any
+         * HC registers. This allows the HC to complete the
+         * reset operation and be ready for HC register access.
+         * Without this delay, the subsequent HC register access,
+         * may result in a system hang very rarely.
+         */
+        if (xhci->quirks & XHCI_INTEL_HOST)
+                udelay(1000);
+
         ret = xhci_handshake(&xhci->op_regs->command,
                         CMD_RESET, 0, 10 * 1000 * 1000);
         if (ret)