Hi Pawel, On Wednesday 25 June 2014 11:46:24 Pawel Osciak wrote: > On Tue, Jun 17, 2014 at 11:45 PM, Vincent Palatin wrote: > > Map V4L2_CID_TILT_RELATIVE and V4L2_CID_PAN_RELATIVE to the standard UVC > > CT_PANTILT_RELATIVE_CONTROL terminal control request. > > > > Tested by plugging a Logitech ConferenceCam C3000e USB camera > > and controlling pan/tilt from the userspace using the VIDIOC_S_CTRL ioctl. > > Verified that it can pan and tilt at the same time in both directions. > > > > Signed-off-by: Vincent Palatin <vpalatin@xxxxxxxxxxxx> > > > > Change-Id: I7b70b228e5c0126683f5f0be34ffd2807f5783dc > > --- > > > > Changes > > v2: fix control request name in description. > > The patch looks good, but I have a more general comment for everyone to > consider. This doesn't match the expected functionality of > controls V4L2_CID_PAN/TILT_RELATIVE. This is basically an on/off switch for > pan/tilt, which once enabled will keep going until turned off (or I'm > guessing until the maximum pan/tilt is reached), while the controls are > supposed to expose an ability to turn the camera by a specified amount. > Here the amount will also be ignored... I agree with you here, and this mismatch between the V4L and UVC controls is the reason why I haven't implemented relative pan/tilt support. > Given that this is a standard UVC control, perhaps we need new V4L2 > controls for it, as I'm assuming we can't change the meaning of existing > controls? We could extend the meaning of the controls to cover the UVC behaviour in a device-specific fashion, but that would be confusing for applications, so new controls might be a better idea. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
