VideoCapture unknown property string (Bug #1895)

I'm trying to get the properties of my webcam using the function VideoCapture::get.

Most of properties returned are -1, and some errors are printed in the console:
Code:

cout << cam.get(CV_CAP_PROP_POS_MSEC) << endl;
cout << cam.get(CV_CAP_PROP_POS_FRAMES) << endl;
cout << cam.get(CV_CAP_PROP_POS_AVI_RATIO) << endl;
cout << cam.get(CV_CAP_PROP_FRAME_WIDTH) << endl;
cout << cam.get(CV_CAP_PROP_FRAME_HEIGHT) << endl;
cout << cam.get(CV_CAP_PROP_FPS) << endl;
cout << cam.get(CV_CAP_PROP_FOURCC) << endl;
cout << cam.get(CV_CAP_PROP_FRAME_COUNT) << endl;
cout << cam.get(CV_CAP_PROP_FORMAT) << endl;
cout << cam.get(CV_CAP_PROP_MODE) << endl;
cout << cam.get(CV_CAP_PROP_BRIGHTNESS) << endl;
cout << cam.get(CV_CAP_PROP_CONTRAST) << endl;
cout << cam.get(CV_CAP_PROP_SATURATION) << endl;
cout << cam.get(CV_CAP_PROP_HUE) << endl;
cout << cam.get(CV_CAP_PROP_GAIN) << endl;
cout << cam.get(CV_CAP_PROP_EXPOSURE) << endl;
cout << cam.get(CV_CAP_PROP_CONVERT_RGB) << endl;
cout << cam.get(CV_CAP_PROP_RECTIFICATION) << endl;


Properties:
-1
-1
-1
640
480
-1
-1
-1
-1
-1
0.501961
0.12549
0.12549
0
0.0862745
-1
-1
-1

Errors:
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(0) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(1) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(2) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(5) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(6) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(7) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(8) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(9) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property Hue(9963779) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property Exposure(9963793) - Argument invalide
HIGHGUI ERROR: V4L: Exposure control in V4L is not supported
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(16) - Argument invalide
HIGHGUI ERROR: V4L2: Unable to get property <unknown property string>(18) - Argument invalide

The main problem in my case is I can't get the frame rate, this <unknown property string>(5) may the the root of this problem, V4L2 doesn't know what I want.
Furthermore, the documentation tells "When querying a property that is not supported by the backend used by the VideoCapture class, value 0 is returned.", and I get a lot of '-1'.

I'm using opencv 2.4 (rev 8315), on Fedora 16.
My wecam is a Logitech HD. I can use it with cheese and I can set parameters.