CS_LEFT_LINE_CONTROL
{ CS_LEFT_LINE_CONTROL, CS_RIGHT_LINE_CONTROL, LINE_INPUT_ATTEN_BITS,
tmp1 = ad_read(sc, CS_LEFT_LINE_CONTROL);
ad_write(sc, CS_LEFT_LINE_CONTROL, 0xe0);
tmp2 = ad_read(sc, CS_LEFT_LINE_CONTROL);
ad_write(sc, CS_LEFT_LINE_CONTROL, tmp1);