* Re: [git:v4l-dvb/master] V4L/DVB: uvcvideo: Clamp control values to the minimum and maximum values
[not found] <E1Njfbf-0000g0-7v@www.linuxtv.org>
@ 2010-02-22 23:11 ` Laurent Pinchart
2010-02-22 23:21 ` Mauro Carvalho Chehab
0 siblings, 1 reply; 2+ messages in thread
From: Laurent Pinchart @ 2010-02-22 23:11 UTC (permalink / raw)
To: Mauro Carvalho Chehab; +Cc: linux-media, MXXrton NXXmeth
Hi Mauro,
On Monday 22 February 2010 22:14:19 Patch from Laurent Pinchart wrote:
> From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> MIME-Version: 1.0
> Content-Type: text/plain; charset=utf-8
> Content-Transfer-Encoding: 8bit
There's a problem somewhere.
> When setting a control, the V4L2 specification requires drivers to
> either clamp the control value to the [minimum, maximum] range or return
> the -ERANGE error.
>
> Fix the driver to clamp control values to the valid range in
> uvc_ctrl_set() and make sure the value differs from the minimum by an
> integer multiple of step.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Tested-by: Márton Németh <nm127@freemail.hu>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
>
> drivers/media/video/uvc/uvc_ctrl.c | 47
> ++++++++++++++++++++++++++++++++--- drivers/media/video/uvc/uvc_v4l2.c |
> 2 +
> 2 files changed, 45 insertions(+), 4 deletions(-)
>
> ---
>
> http://git.linuxtv.org/v4l-dvb.git?a=commitdiff;h=a8677cd5589be9e35ef5117f7
> 5e4b996724102fb
>
> diff --git a/drivers/media/video/uvc/uvc_ctrl.c
> b/drivers/media/video/uvc/uvc_ctrl.c index 5ff5013..f38bc6b 100644
> --- a/drivers/media/video/uvc/uvc_ctrl.c
> +++ b/drivers/media/video/uvc/uvc_ctrl.c
> @@ -1021,19 +1021,57 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
> {
> struct uvc_control *ctrl;
> struct uvc_control_mapping *mapping;
> - s32 value = xctrl->value;
> + s32 value;
> + u32 step;
> + s32 min;
> + s32 max;
> int ret;
>
> ctrl = uvc_find_control(chain, xctrl->id, &mapping);
> if (ctrl == NULL || (ctrl->info->flags & UVC_CONTROL_SET_CUR) == 0)
> return -EINVAL;
>
> - if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
> - if (value < 0 || value >= mapping->menu_count)
> + /* Clamp out of range values. */
> + switch (mapping->v4l2_type) {
> + case V4L2_CTRL_TYPE_INTEGER:
> + if (!ctrl->cached) {
> + ret = uvc_ctrl_populate_cache(chain, ctrl);
> + if (ret < 0)
> + return ret;
> + }
> +
> + min = mapping->get(mapping, UVC_GET_MIN,
> + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN));
> + max = mapping->get(mapping, UVC_GET_MAX,
> + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
> + step = mapping->get(mapping, UVC_GET_RES,
> + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES));
> +
> + xctrl->value = min + (xctrl->value - min + step/2) / step * step;
> + xctrl->value = clamp(xctrl->value, min, max);
> + value = xctrl->value;
> + break;
> +
> + case V4L2_CTRL_TYPE_BOOLEAN:
> + xctrl->value = clamp(xctrl->value, 0, 1);
> + value = xctrl->value;
> + break;
> +
> + case V4L2_CTRL_TYPE_MENU:
> + if (xctrl->value < 0 || xctrl->value >= mapping->menu_count)
> return -ERANGE;
> - value = mapping->menu_info[value].value;
> + value = mapping->menu_info[xctrl->value].value;
> + break;
> +
> + default:
> + value = xctrl->value;
> + break;
> }
>
> + /* If the mapping doesn't span the whole UVC control, the current value
> + * needs to be loaded from the device to perform the read-modify-write
> + * operation.
> + */
> if (!ctrl->loaded && (ctrl->info->size * 8) != mapping->size) {
> if ((ctrl->info->flags & UVC_CONTROL_GET_CUR) == 0) {
> memset(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
> @@ -1051,6 +1089,7 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
> ctrl->loaded = 1;
> }
>
> + /* Backup the current value in case we need to rollback later. */
> if (!ctrl->dirty) {
> memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
> uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
> diff --git a/drivers/media/video/uvc/uvc_v4l2.c
> b/drivers/media/video/uvc/uvc_v4l2.c index 23239a4..bf1fc7f 100644
> --- a/drivers/media/video/uvc/uvc_v4l2.c
> +++ b/drivers/media/video/uvc/uvc_v4l2.c
> @@ -549,6 +549,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg) return ret;
> }
> ret = uvc_ctrl_commit(chain);
> + if (ret == 0)
> + ctrl->value = xctrl.value;
> break;
> }
--
Regards,
Laurent Pinchart
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