Sound OK using built-in speakers, but loud "static" with headphones

[David Wolfskill]

On Thu, Apr 16, 2015 at 10:31:26AM -0700, David Wolfskill wrote:
> This is on a fairly new laptop (ref.
> <https://wiki.freebsd.org/Laptops/Dell_Precision_M4800>, so there is
> some probability that there's an electrical or mechanical issue with the
> hardware... but I'd like to eliminate other possibilities before losing
> the ability to use the machine for several days.
> ...

I discovered "sysctl dev.hdac.0.pindump=1"; here are the corresponding
pin dumps to go with:

g1-254(10.1-S)[24] cat /dev/sndstat 
Installed devices:
pcm0: <NVIDIA (0x0042) (HDMI/DP 8ch)> (play)
pcm1: <NVIDIA (0x0042) (HDMI/DP 8ch)> (play)
pcm2: <Realtek (0x0292) (Analog 2.0+HP/2.0)> (play/rec) default
pcm3: <Realtek (0x0292) (Analog)> (play/rec)
g1-254(10.1-S)[25] 

hdaa0: Dumping AFG pins:
hdaa0: nid   0x    as seq device       conn  jack    loc        color   misc
hdaa0:  4 585600f0 15 0  Digital-out   None  Digital 0x18       Unknown 0 DISA
hdaa0:     Caps:    OUT              Sense: 0x00000000 (disconnected)
hdaa0:  5 185600f0 15 0  Digital-out   Jack  Digital 0x18       Unknown 0
hdaa0:     Caps:    OUT              Sense: 0x00000000 (disconnected)
hdaa0:  6 585600f0 15 0  Digital-out   None  Digital 0x18       Unknown 0 DISA
hdaa0:     Caps:    OUT              Sense: 0x00000000 (disconnected)
hdaa0:  7 185600f0 15 0  Digital-out   Jack  Digital 0x18       Unknown 0
hdaa0:     Caps:    OUT              Sense: 0x00000000 (disconnected)
hdaa0: NumGPIO=0 NumGPO=0 NumGPI=0 GPIWake=0 GPIUnsol=0
hdaa1: Dumping AFG pins:
hdaa1: nid   0x    as seq device       conn  jack    loc        color   misc
hdaa1: 18 90a60140 4  0  Mic           Fixed Digital Internal   Unknown 1
hdaa1:     Caps: IN                 
hdaa1: 19 411111f0 15 0  Speaker       None  1/8     Rear       Black   1 DISA
hdaa1:     Caps: IN                 
hdaa1: 20 90170110 1  0  Speaker       Fixed Analog  Internal   Unknown 1
hdaa1:     Caps:    OUT    EAPD     
hdaa1: 21 0221401f 1  15 Headphones    Jack  1/8     Front      Green   0
hdaa1:     Caps:    OUT HP EAPD      Sense: 0x00000000 (disconnected)
hdaa1: 22 01014020 2  0  Line-out      Jack  1/8     Rear       Green   0
hdaa1:     Caps:    OUT HP EAPD      Sense: 0x00000000 (disconnected)
hdaa1: 24 02a19031 3  1  Mic           Jack  1/8     Front      Pink    0
hdaa1:     Caps: IN OUT         VREF Sense: 0x00000000 (disconnected)
hdaa1: 25 01a1903e 3  14 Mic           Jack  1/8     Rear       Pink    0
hdaa1:     Caps: IN                  Sense: 0x00000000 (disconnected)
hdaa1: 26 411111f0 15 0  Speaker       None  1/8     Rear       Black   1 DISA
hdaa1:     Caps: IN             VREF Sense: 0x00000000 (disconnected)
hdaa1: 27 411111f0 15 0  Speaker       None  1/8     Rear       Black   1 DISA
hdaa1:     Caps: IN OUT         VREF Sense: 0x00000000 (disconnected)
hdaa1: 30 411111f0 15 0  Speaker       None  1/8     Rear       Black   1 DISA
hdaa1:     Caps:    OUT              Sense: 0x00000000 (disconnected)
hdaa1: NumGPIO=5 NumGPO=0 NumGPI=0 GPIWake=0 GPIUnsol=1
hdaa1:  GPIO0: disabled
hdaa1:  GPIO1: disabled
hdaa1:  GPIO2: disabled
hdaa1:  GPIO3: disabled
hdaa1:  GPIO4: disabled


Maybe there's something I can do with those pin assignments to stop
the unwanted noise from going to the headphones (or anywhere else)...?

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Those who murder in the name of God or prophet are blasphemous cowards.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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