ac97_patch.c provides two helper functions that wrap the channel_mode variable, but they only take you out to 5.1 Audio:

static inline int is_surround_on(struct snd_ac97 *ac97) { return ac97->channel_mode >= 1; }

static inline int is_clfe_on(struct snd_ac97 *ac97) { return ac97->channel_mode >= 2; }

For 7.1 Audio, i think there needs to be a test for 'Surround Back' or 'Back Surround'

static inline int is_surback_on(struct snd_ac97 *ac97) { return ac97->channel_mode >= 4; }

Am i correct? or am i mistaken? agreement or corrections appreciated!

I think that i need this function for implementing vt1618_update_jacks() because vt1618 is 7.1 Audio:

static void vt1618_update_jacks(struct snd_ac97 *ac97) { unsigned short usSft = 0, usMsk = 0x0003;

if(is_surround_on(ac97)) ac97_update_bits_page(ac97, 0x60, 0x000C, ucontrol->value.enumerated.item[0]<<2, 0);

if(is_clfe_on(ac97)) ac97_update_bits_page(ac97, 0x60, 0x0030, ucontrol->value.enumerated.item[0]<<4, 0);

if(is_surback_on(ac97)) { /* toggle surround rear dac power */

snd_ac97_update_bits(ac97, 0x5c, 0x0008, ucontrol->value.enumerated.item[0] << 3);

/* toggle aux in surround rear out jack */

snd_ac97_update_bits(ac97, 0x76, 0x0008, ucontrol->value.enumerated.item[0] << 3); } }