ess_read
static int ess_read(struct ess_info *sc, u_char reg);
ess_write(sc, 0xb8, ess_read(sc, 0xb8) & ~0x01);
ess_write(sc, 0xb8, ess_read(sc, 0xb8) & ~0x01);
ess_write(sc, 0xa8, (ess_read(sc, 0xa8) & ~0x03) | (stereo? 0x01 : 0x02));
ess_write(sc, 0xb1, (ess_read(sc, 0xb1) & 0x0f) | 0x50);
ess_write(sc, 0xb2, (ess_read(sc, 0xb2) & 0x0f) | 0x50);
ess_write(sc, 0xb8, ess_read(sc, 0xb8) | 0x01);
ess_write(sc, 0xb8, ess_read(sc, 0xb8) & ~0x04);