1 files changed, 29 insertions, 4 deletions

diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index f34d524ccb09..a83131bd00b2 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -1387,6 +1387,27 @@ static int vidioc_queryctrl(struct file *file, void *priv,
                 return -EINVAL;
 }
 
+/*
+ * FIXME: This is an indirect way to check if a control exists at a
+ * subdev. Instead of that hack, maybe the better would be to change all
+ * subdevs to return -ENOIOCTLCMD, if an ioctl is not supported.
+ */
+static int check_subdev_ctrl(struct em28xx *dev, int id)
+{
+        struct v4l2_queryctrl qc;
+
+        memset(&qc, 0, sizeof(qc));
+        qc.id = id;
+
+        /* enumerate V4L2 device controls */
+        v4l2_device_call_all(&dev->v4l2_dev, 0, core, queryctrl, &qc);
+
+        if (qc.type)
+                return 0;
+        else
+                return -EINVAL;
+}
+
 static int vidioc_g_ctrl(struct file *file, void *priv,
                                 struct v4l2_control *ctrl)
 {
@@ -1399,7 +1420,6 @@ static int vidioc_g_ctrl(struct file *file, void *priv,
                 return rc;
         rc = 0;
 
-
         /* Set an AC97 control */
         if (dev->audio_mode.ac97 != EM28XX_NO_AC97)
                 rc = ac97_get_ctrl(dev, ctrl);
@@ -1408,6 +1428,9 @@ static int vidioc_g_ctrl(struct file *file, void *priv,
 
         /* It were not an AC97 control. Sends it to the v4l2 dev interface */
         if (rc == 1) {
+                if (check_subdev_ctrl(dev, ctrl->id))
+                        return -EINVAL;
+
                 v4l2_device_call_all(&dev->v4l2_dev, 0, core, g_ctrl, ctrl);
                 rc = 0;
         }
@@ -1434,8 +1457,10 @@ static int vidioc_s_ctrl(struct file *file, void *priv,
 
         /* It isn't an AC97 control. Sends it to the v4l2 dev interface */
         if (rc == 1) {
-                rc = v4l2_device_call_until_err(&dev->v4l2_dev, 0, core, s_ctrl, ctrl);
-
+                rc = check_subdev_ctrl(dev, ctrl->id);
+                if (!rc)
+                        v4l2_device_call_all(&dev->v4l2_dev, 0,
+                                             core, s_ctrl, ctrl);
                 /*
                  * In the case of non-AC97 volume controls, we still need
                  * to do some setups at em28xx, in order to mute/unmute
@@ -1452,7 +1477,7 @@ static int vidioc_s_ctrl(struct file *file, void *priv,
                         rc = em28xx_audio_analog_set(dev);
                 }
         }
-        return rc;
+        return (rc < 0) ? rc : 0;
 }
 
 static int vidioc_g_tuner(struct file *file, void *priv,