Comment 18 for bug 1074615

this mean that 0x1b is the pin complex for ext mic

you need to change the pin default of node 0x1a from [Jack] to.[N/A]

00b The Port Complex is connected to a jack (1/8", ATAPI, etc.)
01b No physical connection for Port.

change pin default of node 0x1a to 0x43a1103e

Node 0x1a [Pin Complex] wcaps 0x400481: Stereo
  Control: name="Mic Jack", index=0, device=0
  Pincap 0x00001324: IN Detect
    Vref caps: HIZ 50 80
  Pin Default 0x03a1103e: [Jack] Mic at Ext Left
    Conn = 1/8, Color = Black
    DefAssociation = 0x3, Sequence = 0xe
  Pin-ctls: 0x24: IN VREF_80
  Unsolicited: tag=03, enabled=1
  Power states: D0 D1 D2 D3 D3cold EPSS
  Power: setting=D0, actual=D0
Node 0x1b [Pin Complex] wcaps 0x400581: Stereo
  Control: name="Mic Jack", index=1, device=0
  Pincap 0x00011334: IN OUT EAPD Detect
    Vref caps: HIZ 50 80
  EAPD 0x2: EAPD
  Pin Default 0x03a19030: [Jack] Mic at Ext Left
    Conn = 1/8, Color = Pink
    DefAssociation = 0x3, Sequence = 0x0
  Pin-ctls: 0x24: IN VREF_80
  Unsolicited: tag=04, enabled=1
  Power states: D0 D1 D2 D3 D3cold EPSS
  Power: setting=D0, actual=D0
  Connection: 2
     0x10* 0x11

http://git.kernel.org/?p=linux/kernel/git/tiwai/sound.git;a=blob_plain;f=Documentation/sound/alsa/HD-Audio.txt;hb=HEAD

Early Patching
~~~~~~~~~~~~~~
When CONFIG_SND_HDA_PATCH_LOADER=y is set, you can pass a "patch" as a
firmware file for modifying the HD-audio setup before initializing the
codec. This can work basically like the reconfiguration via sysfs in
the above, but it does it before the first codec configuration.

A patch file is a plain text file which looks like below:

------------------------------------------------------------------------
  [codec]
  0x12345678 0xabcd1234 2

  [model]
  auto

  [pincfg]
  0x12 0x411111f0

  [verb]
  0x20 0x500 0x03
  0x20 0x400 0xff

  [hint]
  hp_detect = yes
------------------------------------------------------------------------

The file needs to have a line `[codec]`. The next line should contain
three numbers indicating the codec vendor-id (0x12345678 in the
example), the codec subsystem-id (0xabcd1234) and the address (2) of
the codec. The rest patch entries are applied to this specified codec
until another codec entry is given. Passing 0 or a negative number to
the first or the second value will make the check of the corresponding
field be skipped. It'll be useful for really broken devices that don't
initialize SSID properly.

The `[model]` line allows to change the model name of the each codec.
In the example above, it will be changed to model=auto.
Note that this overrides the module option.

After the `[pincfg]` line, the contents are parsed as the initial
default pin-configurations just like `user_pin_configs` sysfs above.
The values can be shown in user_pin_configs sysfs file, too.

Similarly, the lines after `[verb]` are parsed as `init_verbs`
sysfs entries, and the lines after `[hint]` are parsed as `hints`
sysfs entries, respectively.

Another example to override the codec vendor id from 0x12345678 to
0xdeadbeef is like below:
------------------------------------------------------------------------
  [codec]
  0x12345678 0xabcd1234 2

  [vendor_id]
  0xdeadbeef
------------------------------------------------------------------------

In the similar way, you can override the codec subsystem_id via
`[subsystem_id]`, the revision id via `[revision_id]` line.
Also, the codec chip name can be rewritten via `[chip_name]` line.
------------------------------------------------------------------------
  [codec]
  0x12345678 0xabcd1234 2

  [subsystem_id]
  0xffff1111

  [revision_id]
  0x10

  [chip_name]
  My-own NEWS-0002
------------------------------------------------------------------------

The hd-audio driver reads the file via request_firmware(). Thus,
a patch file has to be located on the appropriate firmware path,
typically, /lib/firmware. For example, when you pass the option
`patch=hda-init.fw`, the file /lib/firmware/hda-init.fw must be
present.

The patch module option is specific to each card instance, and you
need to give one file name for each instance, separated by commas.
For example, if you have two cards, one for an on-board analog and one
for an HDMI video board, you may pass patch option like below:
------------------------------------------------------------------------
    options snd-hda-intel patch=on-board-patch,hdmi-patch
-----------------------------------------------------------------------