Patch "[media] media/v4l2-ctrls: fix setting autocluster to manual with VIDIOC_S_CTRL" has been added to the 4.3-stable tree

This is a note to let you know that I've just added the patch titled

    [media] media/v4l2-ctrls: fix setting autocluster to manual with VIDIOC_S_CTRL

to the 4.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     media-v4l2-ctrls-fix-setting-autocluster-to-manual-with-vidioc_s_ctrl.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.

From 759b26a1d916400a1a20948eb964dea6ad0bd9e9 Mon Sep 17 00:00:00 2001

From: Antonio Ospite <redacted>
Date: Wed, 14 Oct 2015 10:57:32 -0300
Subject: [media] media/v4l2-ctrls: fix setting autocluster to manual with VIDIOC_S_CTRL

From: Antonio Ospite <redacted>

commit 759b26a1d916400a1a20948eb964dea6ad0bd9e9 upstream.

Since commit 5d0360a4f027576e5419d4a7c711c9ca0f1be8ca it's not possible
anymore to set auto clusters from auto to manual using VIDIOC_S_CTRL.

For example, setting autogain to manual with gspca/ov534 driver and this
sequence of commands does not work:

  v4l2-ctl --set-ctrl=gain_automatic=1
  v4l2-ctl --list-ctrls | grep gain_automatic
  # The following does not work
  v4l2-ctl --set-ctrl=gain_automatic=0
  v4l2-ctl --list-ctrls | grep gain_automatic

Changing the value using VIDIOC_S_EXT_CTRLS (like qv4l2 does) works
fine.

The apparent cause by looking at the changes in 5d0360a and comparing
with the code path for VIDIOC_S_EXT_CTRLS seems to be that the code in
v4l2-ctrls.c::set_ctrl() is not calling user_to_new() anymore after
calling update_from_auto_cluster(master).

However the root cause of the problem is that calling
update_from_auto_cluster(master) overrides also the _master_ control
state calling cur_to_new() while it was supposed to only update the
volatile controls.

Calling user_to_new() after update_from_auto_cluster(master) was just
masking the original bug by restoring the correct new value of the
master control before making the changes permanent.

Fix the original bug by making update_from_auto_cluster() not override
the new master control value.

Signed-off-by: Antonio Ospite <redacted>
Signed-off-by: Hans Verkuil <redacted>
Signed-off-by: Mauro Carvalho Chehab <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/v4l2-core/v4l2-ctrls.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c

@@ -3043,7 +3043,7 @@ static void update_from_auto_cluster(str
 {
 	int i;
 
-	for (i = 0; i < master->ncontrols; i++)
+	for (i = 1; i < master->ncontrols; i++)
 		cur_to_new(master->cluster[i]);
 	if (!call_op(master, g_volatile_ctrl))
 		for (i = 1; i < master->ncontrols; i++)

Patches currently in stable-queue which might be from ao2@ao2.it are

queue-4.3/media-v4l2-ctrls-fix-setting-autocluster-to-manual-with-vidioc_s_ctrl.patch