pwc_whitebalance  253 include/media/pwc-ioctl.h #define VIDIOCPWCSAWB           _IOW('v', 202, struct pwc_whitebalance)
pwc_whitebalance  254 include/media/pwc-ioctl.h #define VIDIOCPWCGAWB           _IOR('v', 202, struct pwc_whitebalance)