On Tue, 2017-10-24 at 21:14 +0100, Adam Sampson wrote:
> 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@xxxxxxxxx>
Thank you!
Reviewed-By: Lubomir Rintel <lkundrak@xxxxx>
> ---
> 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 95b5f43..3668a04 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;
