When compiling dvb_frontend.c compiler returns an error at line 707: implicit declaration of function 'init_MUTEX'.
Kernel build directory is /lib/modules/2.6.31-9-rt/build
/home/tomislav/v4l-dvb/v4l/dvb_frontend.c: In function 'dvb_frontend_stop':
/home/tomislav/v4l-dvb/v4l/dvb_frontend.c:707: error: implicit declaration of function 'init_MUTEX'
Correct me of I'm wrong, but as I understand (not really an expert), the usage of semaphores as mutexes is deprecated and apparently it has been removed from new realtime kernels. Obviously, there is no init_MUTEX macro in semaphores.h of 2.6.31-9-rt.