Comment 45 for bug 1302090

you are using old version of alsa driver if you still find the name is alc668 since the driver had rename alc668 on those dell computers to alc3661

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/pci/hda?id=4b016931a997be59a2be0da3398985a19fdfa5be

static struct alc_codec_rename_pci_table rename_pci_tbl[] = {
+ { 0x10ec0280, 0x1028, 0, "ALC3220" },
+ { 0x10ec0282, 0x1028, 0, "ALC3221" },
+ { 0x10ec0283, 0x1028, 0, "ALC3223" },
+ { 0x10ec0292, 0x1028, 0, "ALC3226" },
+ { 0x10ec0255, 0x1028, 0, "ALC3234" },
+ { 0x10ec0668, 0x1028, 0, "ALC3661" },
+ { } /* terminator */
+};