The "fake" controls added by libv4l to provide whitebalance on some cameras do
not respect the V4L2_CTRL_FLAG_NEXT_CTRL and hence don't appear on control
programs that try to use that flag if there are any driver controls that do
support the flag. Add support for V4L2_CTRL_FLAG_NEXT_CTRL
Signed-off-by: Adam Baker <linux@xxxxxxxxxxxxxxxx>
---
This isn't extensively tested but v4l2ucp (and my version does use the flag) now
lists both fake and original control for a camera with both and adds the fake controls
for a camera with none.
---
--- libv4l-0.5.97/libv4lconvert/control/libv4lcontrol.c 2009-04-14 09:17:02.000000000 +0100
+++ new/libv4lconvert/control/libv4lcontrol.c 2009-04-18 23:36:28.000000000 +0100
@@ -280,7 +280,10 @@
{
int i;
struct v4l2_queryctrl *ctrl = arg;
+ int retval;
+ __u32 orig_id=ctrl->id;
+ /* if we have an exact match return it */
for (i = 0; i < V4LCONTROL_COUNT; i++)
if ((data->controls & (1 << i)) &&
ctrl->id == fake_controls[i].id) {
@@ -288,7 +291,21 @@
return 0;
}
- return syscall(SYS_ioctl, data->fd, VIDIOC_QUERYCTRL, arg);
+ /* find out what the kernel driver would respond. */
+ retval = syscall(SYS_ioctl, data->fd, VIDIOC_QUERYCTRL, arg);
+
+ /* if any of our controls have an id > orig_id but less than
+ ctrl->id then return that control instead. */
+ if (orig_id & V4L2_CTRL_FLAG_NEXT_CTRL)
+ for (i = 0; i < V4LCONTROL_COUNT; i++)
+ if ((data->controls & (1 << i)) &&
+ (fake_controls[i].id > (orig_id & ~V4L2_CTRL_FLAG_NEXT_CTRL)) &&
+ (fake_controls[i].id <= ctrl->id)) {
+ memcpy(ctrl, &fake_controls[i], sizeof(struct v4l2_queryctrl));
+ retval = 0;
+ }
+
+ return retval;
}
int v4lcontrol_vidioc_g_ctrl(struct v4lcontrol_data *data, void *arg)
--
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