Re: [PATCH] media: uvcvideo: Prevent setting unavailable flags
From: Guennadi Liakhovetski
Date: Wed Apr 11 2018 - 15:33:12 EST
Hi Kieran,
Thanks for the patch, it fixed a problem I was having with media master,
working with a Logitech UVC 1.5 camera.
On Wed, 21 Mar 2018, Kieran Bingham wrote:
> The addition of an extra operation to use the GET_INFO command
> overwrites all existing flags from the uvc_ctrls table. This includes
> setting all controls as supporting GET_MIN, GET_MAX, GET_RES, and
> GET_DEF regardless of whether they do or not.
>
> Move the initialisation of these control capabilities directly to the
> uvc_ctrl_fill_xu_info() call where they were originally located in that
> use case, and ensure that the new functionality in uvc_ctrl_get_flags()
> will only set flags based on their reported capability from the GET_INFO
> call.
>
> Fixes: 859086ae3636 ("media: uvcvideo: Apply flags from device to actual
> properties")
>
> Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
Tested-by: Guennadi Liakhovetski <guennadi.liakhovetski@xxxxxxxxx>
Thanks
Guennadi
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 17 +++++++++--------
> 1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 1daf444371be..4042cbdb721b 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1607,14 +1607,12 @@ static int uvc_ctrl_get_flags(struct uvc_device *dev,
> ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
> info->selector, data, 1);
> if (!ret)
> - info->flags = UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
> - | UVC_CTRL_FLAG_GET_RES | UVC_CTRL_FLAG_GET_DEF
> - | (data[0] & UVC_CONTROL_CAP_GET ?
> - UVC_CTRL_FLAG_GET_CUR : 0)
> - | (data[0] & UVC_CONTROL_CAP_SET ?
> - UVC_CTRL_FLAG_SET_CUR : 0)
> - | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
> - UVC_CTRL_FLAG_AUTO_UPDATE : 0);
> + info->flags |= (data[0] & UVC_CONTROL_CAP_GET ?
> + UVC_CTRL_FLAG_GET_CUR : 0)
> + | (data[0] & UVC_CONTROL_CAP_SET ?
> + UVC_CTRL_FLAG_SET_CUR : 0)
> + | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
> + UVC_CTRL_FLAG_AUTO_UPDATE : 0);
>
> kfree(data);
> return ret;
> @@ -1689,6 +1687,9 @@ static int uvc_ctrl_fill_xu_info(struct uvc_device *dev,
>
> info->size = le16_to_cpup((__le16 *)data);
>
> + info->flags = UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
> + | UVC_CTRL_FLAG_GET_RES | UVC_CTRL_FLAG_GET_DEF;
> +
> ret = uvc_ctrl_get_flags(dev, ctrl, info);
> if (ret < 0) {
> uvc_trace(UVC_TRACE_CONTROL,
> --
> 2.7.4
>