diff --git a/[refs] b/[refs]
index f6491943947c..345d8c69a77b 100644
--- a/[refs]
+++ b/[refs]
@@ -8,7 +8,7 @@ refs/heads/stable-0.14: 56a60dd6d619877e9957ba06b92d2f276e3c229d
 refs/heads/stable-0.15: 82b2b32a323bbb5824b4fbe63a3bca50f827e28e
 refs/heads/stable-1.0: 3ffb4001c2e28624cd59a2b3598858784d0718d0
 refs/heads/stable-1.1: 4ce5bc2dd1914a706725186c6563e8f92eedfc84
-refs/heads/staging: 94ae9eece7c8192170a4159804e152fa32e9eacf
+refs/heads/staging: 6d3bc22e31bcee74dc1e05a5370cabb33b7c3fda
 refs/tags/v0.5.1: be26a5288e43d3177908a92251c526d54fbb936d
 refs/tags/v0.6.0: ea4b3c0748638ccebd8903f0dd2a8b32c69ab6fe
 "refs/tags/release_0_10_0": 25c4fde17775821182a76fb8ea2ba2223c5729b9
diff --git a/branches/staging/hw/usb/hcd-xhci.c b/branches/staging/hw/usb/hcd-xhci.c
index c0dbc54e1a8c..7f740d9c6d59 100644
--- a/branches/staging/hw/usb/hcd-xhci.c
+++ b/branches/staging/hw/usb/hcd-xhci.c
@@ -3079,8 +3079,15 @@ static void xhci_doorbell_write(void *ptr, hwaddr reg,
     }
 }
 
+static void xhci_cap_write(void *opaque, hwaddr addr, uint64_t val,
+                           unsigned width)
+{
+    /* nothing */
+}
+
 static const MemoryRegionOps xhci_cap_ops = {
     .read = xhci_cap_read,
+    .write = xhci_cap_write,
     .valid.min_access_size = 1,
     .valid.max_access_size = 4,
     .impl.min_access_size = 4,