asterisk users - Mar 2009 - compile error: implicit declaration of function drv_dbg

hello,
I try to open the debug to compile dahdi with wcb4xxp,
=================base.c===========================================#ifdef
DEBUG_LOWLEVEL_REGS
	if (unlikely(DBG_REGS))
		drv_dbg(b4->dev, "read 0x%02x from 0x%p\n", ret, b4->addr +
reg);
#endif
	if (unlikely(pedanticpci)) {
		udelay(3);
	}
===============================================================/usr/src/dahdi-linux/drivers/dahdi/wcb4xxp/base.c:
In function __pci_in8:
/usr/src/dahdi-linux/drivers/dahdi/wcb4xxp/base.c:150: error: implicit
declaration of function drv_dbg
make[3]: *** [/usr/src/dahdi-linux/drivers/dahdi/wcb4xxp/base.o] Error 1
make[2]: *** [/usr/src/dahdi-linux/drivers/dahdi/wcb4xxp] Error 2
make[1]: *** [_module_/usr/src/dahdi-linux/drivers/dahdi] Error 2
make[1]: Leaving directory `/usr/src/kernels/2.6.18-8.el5-i686'
--------------------------------------------------------------
anybody knows how to drv_dbg in dahdi? 
thanks!
lizhon