1 files changed, 31 insertions, 1 deletions

diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c
index 1072e987ff21..ed9b404e5f5a 100644
--- a/drivers/usb/gadget/inode.c
+++ b/drivers/usb/gadget/inode.c
@@ -32,6 +32,7 @@
 #include <linux/compiler.h>
 #include <asm/uaccess.h>
 #include <linux/slab.h>
+#include <linux/poll.h>
 
 #include <linux/device.h>
 #include <linux/moduleparam.h>
@@ -1235,6 +1236,35 @@ dev_release (struct inode *inode, struct file *fd)
         return 0;
 }
 
+static unsigned int
+ep0_poll (struct file *fd, poll_table *wait)
+{
+       struct dev_data         *dev = fd->private_data;
+       int                     mask = 0;
+
+       poll_wait(fd, &dev->wait, wait);
+
+       spin_lock_irq (&dev->lock);
+
+       /* report fd mode change before acting on it */
+       if (dev->setup_abort) {
+               dev->setup_abort = 0;
+               mask = POLLHUP;
+               goto out;
+       }
+
+       if (dev->state == STATE_SETUP) {
+               if (dev->setup_in || dev->setup_can_stall)
+                       mask = POLLOUT;
+       } else {
+               if (dev->ev_next != 0)
+                       mask = POLLIN;
+       }
+out:
+       spin_unlock_irq(&dev->lock);
+       return mask;
+}
+
 static int dev_ioctl (struct inode *inode, struct file *fd,
                 unsigned code, unsigned long value)
 {
@@ -1254,7 +1284,7 @@ static const struct file_operations ep0_io_operations = {
         .read =         ep0_read,
         .write =        ep0_write,
         .fasync =       ep0_fasync,
-        // .poll =      ep0_poll,
+        .poll =         ep0_poll,
         .ioctl =        dev_ioctl,
         .release =      dev_release,
 };