V4L/DVB: uvcvideo: Clamp control values to the minimum and maximum values
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>
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 @@
{
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 @@
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),