Comment 81 for bug 893210

only those in whitelist call snd_ac97_update_bits(ac97, AC97_AD_JACK_SPDIF, 1<<11, 1<<11);

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/sound/pci/ac97/ac97_patch.c

static unsigned int ad1981_jacks_whitelist[] = {
 0x0e11005a, /* HP nc4000/4010 */
 0x103c0890, /* HP nc6000 */
 0x103c0938, /* HP nc4220 */
 0x103c099c, /* HP nx6110 */
 0x103c0944, /* HP nc6220 */
 0x103c0934, /* HP nc8220 */
 0x103c006d, /* HP nx9105 */
 0x103c300d, /* HP Compaq dc5100 SFF(PT003AW) */
 0x17340088, /* FSC Scenic-W */
 0 /* end */
};

static void check_ad1981_hp_jack_sense(struct snd_ac97 *ac97)
{
 if (check_list(ac97, ad1981_jacks_whitelist))
  /* enable headphone jack sense */
  snd_ac97_update_bits(ac97, AC97_AD_JACK_SPDIF, 1<<11, 1<<11);
}