V4L/DVB: V4L: Events: Support event handling in do_ioctl

Add support for event handling to do_ioctl.

Signed-off-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/media/video/v4l2-fh.c b/drivers/media/video/v4l2-fh.c
index aab2fb639ef1..d78f184f40c5 100644
--- a/drivers/media/video/v4l2-fh.c
+++ b/drivers/media/video/v4l2-fh.c
@@ -34,7 +34,16 @@ int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
         INIT_LIST_HEAD(&fh->list);
         set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
 
-        return v4l2_event_init(fh);
+        /*
+         * fh->events only needs to be initialized if the driver
+         * supports the VIDIOC_SUBSCRIBE_EVENT ioctl.
+         */
+        if (vdev->ioctl_ops && vdev->ioctl_ops->vidioc_subscribe_event)
+                return v4l2_event_init(fh);
+
+        fh->events = NULL;
+
+        return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_fh_init);