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V4L/DVB: uvcvideo: Clamp control values to the minimum and maximum values

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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>
This commit is contained in:
Laurent Pinchart 2010-01-23 07:07:53 -03:00 committed by Mauro Carvalho Chehab
parent 59529081e0
commit e54532e591
2 changed files with 45 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/media/video/uvc/uvc_ctrl.c
View File

@ -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),

2
drivers/media/video/uvc/uvc_v4l2.c
View File

@ -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;
}