rem: DACW(TSTCTRL, (DACR(TSTCTRL) | 0x00010000));
add: DACW(TSTCTRL, (DACR(TSTCTRL) & 0xfffeffff));
context: bool nv_dac_crt_connected(void){	uint32 output, dac;	bool present;	/* save output connector setting */	output = DACR(OUTPUT);	/* save DAC state */	dac = DACR(TSTCTRL);	/* shut-off DAC */	DACW(TSTCTRL, (DACR(TSTCTRL) | 0x00010000));	/* select primary head and turn off CRT (and DVI?) outputs */	DACW(OUTPUT, (output & 0x0000feee));	/* wait for signal lines to stabilize */	snooze(1000);	/* re-enable CRT output */	DACW(OUTPUT, (DACR(OUTPUT) | 0x00000001));	/* setup RGB test signal levels to approx 30% of DAC range and enable them */	DACW(TSTDATA, ((0x2 << 30) | (0x140 << 20) | (0x140 << 10) | (0x140 << 0)));	/* route test signals to output */	DACW(TSTCTRL, (DACR(TSTCTRL) | 0x00001000));	/* wait for signal lines to stabilize */	snooze(1000);	/* do actual detection: all signals paths high == CRT connected */	if DACR(TSTCTRL & 0x10000000)	{		present = true;		LOG(4,("DAC: CRT detected\n"));	}	else	{		present = false;		LOG(4,("DAC: no CRT detected\n"));	}	/* kill test signal routing */	DACW(TSTCTRL, (DACR(TSTCTRL) & 0xffffefff));	/* restore output connector setting */	DACW(OUTPUT, output);	/* restore DAC state */	DACW(TSTCTRL, dac);	return present;}