Comment 2 for bug 1101677

Advanced information - PCI Vendor/Device/Subsystem ID's
!!--------------------------------------------------------

00:1b.0 0403: 8086:284b (rev 02)
 Subsystem: 1028:01f2

http://git.kernel.org/?p=linux/kernel/git/tiwai/sound.git;a=commitdiff;h=dfe495d0a51e20325b51760f34a2f53bfe1f3b52;hp=889c43955115ea7412d71335e3ceff6bad118dce

Your inspiron 1720 was hardcoded a pin fixup

 + SND_PCI_QUIRK(PCI_VENDOR_ID_DELL, 0x01f2,
+ "unknown Dell", STAC_9205_DELL_M42),

Sysfs Files
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/sys/class/sound/hwC0D0/init_pin_configs:
0x0a 0x0421101f
0x0b 0x04811020
0x0c 0x40f000f0
0x0d 0x90170110
0x0e 0x40f000f1
0x0f 0x40f000f2
0x14 0x40f000f3
0x16 0x40f000f4
0x17 0x90a60030
0x18 0x40f000f5
0x21 0x014410a0
0x22 0x40f000f7

/sys/class/sound/hwC0D0/driver_pin_configs:
0x0a 0x0321101f
0x0b 0x03a11020
0x0c 0x400003fa
0x0d 0x90170310
0x0e 0x400003fb
0x0f 0x400003fc
0x14 0x400003fd
0x16 0x40f000f9
0x17 0x90a60330
0x18 0x400003ff
0x21 0x0144131f
0x22 0x40c003fe