From b3168c87c0492661badc3e908f977d79e7738a41 Mon Sep 17 00:00:00 2001
From: Adam Sampson <ats@offog.org>
Date: Tue, 24 Oct 2017 16:14:46 -0400
Subject: [PATCH] media: usbtv: fix brightness and contrast controls
Git-commit: b3168c87c0492661badc3e908f977d79e7738a41
Patch-mainline: v4.15-rc1
References: bsc#1051510

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@offog.org>
Reviewed-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/usb/usbtv/usbtv-video.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- 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
 	 */
 	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;