Hi,
On Thu, 5 Mar 2009, wdy9927 wrote:
I had make install a module for a dvb usb box which writen by my self. But this one didn't have real frontend ops and tuner ops.These functions did
nothing but return 0.
Like this
static int demo_fe_init(struct dvb_frontend *fe)
{
return 0;
}
After the usb box removed from linux, the DVB system called demo_fe_release and demo_tu_release, sofar that seems very good? But, I can't rmmod this
module normally. It showed "ERROR: Module dvb_usb_dvbusb_demo is in use".This error is diffrent with "ERROR: Module dvb_usb is in use by
dvb_usb_dvbusb_demo"
How can i rmmod this module with out reboot Linux.
This is a known problem with every dvb-device-driver (especially the ones
using dvb-usb) which are implementing the frontend-part not as an
independent kernel module. When the frontend-driver is "released" the
dvb-core is doing something like use-count-decrement on the module. As the
use-count was never incremented (dvb_attach cannot be used on function
which are not exported with EXPORT_SYMBOL) the count is now -1, which is
same as 0xffffffff.
rmmod is refusing to unload a module which has a use_count != 0. This is
the problem you're facing.
You could still try to use rmmod -f to force to unload. Or you make your
frontend-driver a seperate kernel module.
Patrick.
