linux-kernel - [PATCH AUTOSEL for 4.14 056/135] media: usbtv: fix brightness and contrast controls

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Message-ID: <20171207154513.4154-56-alexander.levin@verizon.com>
Date:   Thu, 7 Dec 2017 15:45:43 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Adam Sampson <ats@...og.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        "Mauro Carvalho Chehab" <mchehab@...pensource.com>,
        alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.14 056/135] media: usbtv: fix brightness and
 contrast controls

From: Adam Sampson <ats@...og.org>

[ Upstream commit b3168c87c0492661badc3e908f977d79e7738a41 ]

Because the brightness and contrast controls share a register,
usbtv_s_ctrl needs to read the existing values for both controls before
inserting the new value. However, the code accidentally wrote to the
registers (from an uninitialised stack array), rather than reading them.

The user-visible effect of this was that adjusting the brightness would
also set the contrast to a random value, and vice versa -- so it wasn't
possible to correctly adjust the brightness of usbtv's video output.

Tested with an "EasyDAY" UTV007 device.

Fixes: c53a846c48f2 ("usbtv: add video controls")

Signed-off-by: Adam Sampson <ats@...og.org>
Reviewed-by: Lubomir Rintel <lkundrak@...sk>
Signed-off-by: Hans Verkuil <hans.verkuil@...co.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...pensource.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/media/usb/usbtv/usbtv-video.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/usbtv/usbtv-video.c b/drivers/media/usb/usbtv/usbtv-video.c
index 95b5f4319ec2..3668a04359e8 100644
--- a/drivers/media/usb/usbtv/usbtv-video.c
+++ b/drivers/media/usb/usbtv/usbtv-video.c
@@ -718,8 +718,8 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
 	 */
 	if (ctrl->id == V4L2_CID_BRIGHTNESS || ctrl->id == V4L2_CID_CONTRAST) {
 		ret = usb_control_msg(usbtv->udev,
-			usb_sndctrlpipe(usbtv->udev, 0), USBTV_CONTROL_REG,
-			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			usb_rcvctrlpipe(usbtv->udev, 0), USBTV_CONTROL_REG,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 			0, USBTV_BASE + 0x0244, (void *)data, 3, 0);
 		if (ret < 0)
 			goto error;
-- 
2.11.0