RADEON_BUS_CNTL
OUTREGP( di->regs, RADEON_BUS_CNTL, 0, ~RADEON_BUS_MASTER_DIS );
SHOW_FLOW( 3, "bus_cntl=%" B_PRIx32, INREG( di->regs, RADEON_BUS_CNTL ));
OUTREGP( regs, RADEON_BUS_CNTL, RADEON_BUS_MASTER_DIS, ~RADEON_BUS_MASTER_DIS );