Thank you abishur for your reply.
My actual problem is that my camera does not go into suspend mode at all on the raspberry pi, but does it on every other desktop PC with ubuntu. After some googling I found out, that the common way to put a USB device into suspend mode is by autosuspend, whitch is controlled by the file /sys/bus/usb/devices/x-x.x/power/autosuspend or /level or /control (https://searchcode.com/codesearch/view/37920475/
). But when I go to this location, the only file existing is "persist". So I connected my USB mouse to the Pi and had a look there, and in this case some more "wakeup..." files appeared, but no autosuspend, level or control file.
So I connected the same devices to my desktop ubuntu PC and checked the files, and here all of them are existent. I thought maybe my Raspbian installation went wrong, so I deleted it and installed it again. But no progress. I have opencv and li4l packages installed.
Do you have an idea why my Pi does not create those files?