diff --git a/cdc-acm-tiocgserial.patch b/cdc-acm-tiocgserial.patch
new file mode 100644
index 0000000..ec82506
--- /dev/null
+++ b/cdc-acm-tiocgserial.patch
@@ -0,0 +1,58 @@
+From http://permalink.gmane.org/gmane.linux.usb.general/9236
+
+attempt to diagnose https://bugzilla.redhat.com/show_bug.cgi?id=787607
+
+diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
+index 9543b19..6dcc3a3 100644
+--- a/drivers/usb/class/cdc-acm.c
++++ b/drivers/usb/class/cdc-acm.c
+@@ -39,6 +39,7 @@
+ #include <linux/serial.h>
+ #include <linux/tty_driver.h>
+ #include <linux/tty_flip.h>
++#include <linux/serial.h>
+ #include <linux/module.h>
+ #include <linux/mutex.h>
+ #include <linux/uaccess.h>
+@@ -734,15 +734,40 @@ static int acm_tty_tiocmset(struct tty_s
+ 	return acm_set_control(acm, acm->ctrlout = newctrl);
+ }
+ 
++static int get_serial_info(struct acm *acm, struct serial_struct __user *info)
++{
++	struct serial_struct tmp;
++
++	if (!info)
++		return -EINVAL;
++
++	memset(&tmp, 0, sizeof(tmp));
++	tmp.flags = ASYNC_LOW_LATENCY;
++	tmp.xmit_fifo_size = acm->writesize;
++	tmp.baud_base = le32_to_cpu(acm->line.dwDTERate);
++
++	if (copy_to_user(info, &tmp, sizeof(tmp)))
++		return -EFAULT;
++	else
++		return 0;
++}
++
+ static int acm_tty_ioctl(struct tty_struct *tty,
+ 					unsigned int cmd, unsigned long arg)
+ {
+ 	struct acm *acm = tty->driver_data;
++	int rv = -ENOIOCTLCMD;
+ 
+ 	if (!ACM_READY(acm))
+ 		return -EINVAL;
+ 
+-	return -ENOIOCTLCMD;
++	switch (cmd) {
++	case TIOCGSERIAL: /* gets serial port data */
++		rv = get_serial_info(acm, (struct serial_struct __user *) arg);
++		break;
++	}
++
++	return rv;
+ }
+ 
+ static const __u32 acm_tty_speed[] = {
diff --git a/kernel.spec b/kernel.spec
index a0d1a18..9aff5b5 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -653,6 +653,8 @@ Patch12303: dmar-disable-when-ricoh-multifunction.patch
 Patch13002: revert-efi-rtclock.patch
 Patch13003: efi-dont-map-boot-services-on-32bit.patch
 
+Patch14000: cdc-acm-tiocgserial.patch
+
 Patch20000: utrace.patch
 
 # Flattened devicetree support
@@ -1258,6 +1260,9 @@ ApplyPatch dmar-disable-when-ricoh-multifunction.patch
 ApplyPatch revert-efi-rtclock.patch
 ApplyPatch efi-dont-map-boot-services-on-32bit.patch
 
+# https://bugzilla.redhat.com/show_bug.cgi?id=787607
+ApplyPatch cdc-acm-tiocgserial.patch
+
 # utrace.
 ApplyPatch utrace.patch
 
@@ -1950,6 +1955,9 @@ fi
 # and build.
 
 %changelog
+* Fri Feb 10 2012 Dave Jones <davej@redhat.com>
+- Implement TIOCGSERIAL for acm_tty_ioctl (rhbz 787607)
+
 * Thu Feb 09 2012 Dave Jones <davej@redhat.com>
 - bsg: fix sysfs link remove warning (#787862)