R_EB21
tda_reg("EXTENDED_BYTE_21 = 0x%02x\n", 0xff & regs[R_EB21]);
regs[R_EB21] = 0x33;
regs[R_EB21] = 0xb3;
regs[R_EB21] |= 0x03; /* set agc2_gain to -6 dB */
ret = tda18271_write_regs(fe, R_EB21, 3);
regs[R_EB21] &= ~0x03; /* set agc2_gain to -15 dB */
ret = tda18271_write_regs(fe, R_EB21, 3);