Use the ddi_cb_unregister(9F) function to unregister a callback handler function for a driver.
int ddi_cb_unregister (ddi_cb_handle_t hdl);
Make this call in the driver's detach(9F) entry point. After this call, the driver no longer receives callback actions.
The driver also loses any additional support from the system that it gained from having a registered callback handling function. For example, some interrupt vectors previously made available to the driver are immediately taken back when the driver unregisters its callback handling function. Before returning successfully, the ddi_cb_unregister() function notifies the driver of any final actions that result from losing support from the system.