[alsa-devel] issue with AD1989A HDA codec and alsamixer

[Raymond Yau]

2011/2/7 Vincent Meserette <vmeserette at aldebaran-robotics.com>

>
> I found from where came my problem with the capture gains by adding some
> logs in the hda_codec.c file.
> When I set one of the capture gain, the put_vol_mute function well write in
> the AMP_GAIN_MUTE verb of the corresponding ADC selector (0x0c, 0x0d or 0x0e
> widget) but the mute bit is always set to 1.
> Indeed, the value associated to the AMP_GAIN_MUTE verb is formated as folow
> :
> bits  0 to 6 : gain
> bit 7 : mute
> bits 8 to 11 : index
> bit 12 : set right amp
> bit 13 : set left amp
> bit 14 : set input amp
> bit 15 : set output amp
>
> and alsa sets the value of this register from a080 / b080 to a0b6 / b0b6
> when i change the gain from -58.5 dB to 22.5dB
>
> Do you know how alsa and thus the alsamixer determine the minimum and
> maximum values for the capture gain, and how to say to alsa the the gain is
> only a 7bits step value ?
>

Take a look at HDA Specification 7.3.4.10 Amplifier Capabilities

StepSize (7 bits) indicates the size of each step in the gain range. Each
individual step may be 0-32 dB specified in 0.25-dB steps. A value of 0
indicates 0.25-dB steps, while a value of 127d indicates a 32-dB step.
NumSteps (7 bits) indicates the number of steps in the gain range. There may
be from 1 to 128 steps in the amplifier gain range. (0d means 1 step, 127d
means 128 steps). A value of 0 (1 step) means that the gain is fixed and may
not be changed.
Offset (7 bits) indicates which step is 0 dB. If there are two or more
steps, one of the step values must correspond to a value of 0 dB. The
“Offset” value reflects the value which, if programmed in to the Amplifier
Gain control, would result in a gain of 0 dB.
Mute Capable (1 bit) reports if the respective amplifier is capable of
muting. Muting implies a –infinity gain (no sound passes), but the actual
performance is determined by the hardware.


Node 0x0c [Audio Selector] wcaps 0x30010d: Stereo Amp-Out
  Control: name="Capture Volume", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Capture Switch", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Input Source", index=0, device=0
  Amp-Out caps: ofs=0x27, nsteps=0x36, stepsize=0x05, mute=1
  Amp-Out vals:  [0x25 0x25]
  Connection: 10
     0x38 0x39* 0x3a 0x3b 0x3c 0x18 0x24 0x25 0x3d 0x20
Node 0x0d [Audio Selector] wcaps 0x30010d: Stereo Amp-Out
  Control: name="Capture Volume", index=1, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Capture Switch", index=1, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Input Source", index=1, device=0
  Amp-Out caps: ofs=0x27, nsteps=0x36, stepsize=0x05, mute=1
  Amp-Out vals:  [0xa7 0xa7]
  Connection: 10
     0x38 0x39* 0x3a 0x3b 0x3c 0x18 0x24 0x25 0x3d 0x20
Node 0x0e [Audio Selector] wcaps 0x30010d: Stereo Amp-Out
  Control: name="Capture Volume", index=2, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Capture Switch", index=2, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Input Source", index=2, device=0
  Amp-Out caps: ofs=0x27, nsteps=0x36, stepsize=0x05, mute=1
  Amp-Out vals:  [0xa7 0xa7]
  Connection: 10
     0x38 0x39* 0x3a 0x3b 0x3c 0x18 0x24 0x25 0x3d 0x20