DBG
#define DBG(x) x
#define DBG(x)
#define DBG(fmt, args...) \
#define DBG(fmt, args...) do { } while (0)
#define DBG 0
#define DBG 0
#define DBG 0
#define DBG 0
#define DBG do { kprintf("ng_device: %s\n", __func__ ); } while (0)
#define DBG do {} while (0)
#define DBG 0x86 /* call debugger */