[alsa-devel] [PATCH] ALSA: hda - Don't access stereo amps for mono channel widgets

[Raymond Yau]

> > >
> > > >
> > > > The current HDA generic parser initializes / modifies the amp values
> > > > always in stereo, but this seems causing the problem on ALC3229
codec
> > > > that has a few mono channel widgets: namely, these mono widgets
react
> > > > to actions for both channels equally.
> > > >
> > > > In the driver code, we do care the mono channel and create a control
> > > > only for the left channel (as defined in HD-audio spec) for such a
> > > > node.  When the control is updated, only the left channel value is
> > > > changed.  However, in the resume, the right channel value is also
> > > > restored from the initial value we took as stereo, and this
overwrites
> > > > the left channel value.  This ends up being the silent output as the
> > > > right channel has been never touched and remains muted.
> > > >
> > > > This patch covers the places where unconditional stereo amp accesses
> > > > are done and converts to the conditional accesses.
> > > >
> > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94581
> > >
> > > Seem the number of amp-in vals is not only depend on widget cap mono
> > >
> > > In your example, node 0xf is mono and has only one connection
> > >
> > > Node 0x0f [Audio Mixer] wcaps 0x20010a: Mono Amp-In
> > >   Amp-In caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
> > >   Amp-In vals:  [0x00]
> > >   Connection: 1
> > >      0x0d
> > >
> > > Refer to block diagram in alc272 datasheet
> > >
> > > Node 0xf has two mute switch
> > >
> > > https://launchpadlibrarian.net/200283132/AlsaInfo.txt
> > >
> > > Node 0x0f [Audio Mixer] wcaps 0x20010a: Mono Amp-In
> > >   Amp-In caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
> > >   Amp-In vals:  [0x00] [0x00]
> > >   Connection: 2
> > >      0x02 0x0b
> > >
> > > Refer to HDA Specification
> > >
> > > 7.1.3 Widget Interconnection Rules
> > >
> > > 5. When a stereo widget is an input to a mono widget, only the
L-channel of
> > > the source drives the sink.
> > >
> > > There is one exception to this rule, which allows a mono Mixer Widget
to
> > > mix the L- and R-channels of a single stereo widget into a mono
channel.
> > >
> > > This exception occurs only when the sink widget is: A Mixer Widget,
and Is
> > > identified as “mono,” and Contains exactly one entry in its connection
> > > list, and The single widget identified in its connection list
(source) is
> > > “stereo.”
> > >
> > > In this case, this mixer is required to have two inputs, the first
being
> > > driven by the L-channel of the stereo source and the second by the
> > > R-channel.
> >
> > The signals are summed up in that case, indeed, but what we do care
> > here is about which amp channel value to control.  So, it's irrelevant
> > from the code change.
>
> After reconsidering this, I see your point now.  The widget 0x0f in
> the first example above needs to have stereo (left and right) amp
> values.  What's confusing is that the second case above does *not*
> have stereo amp values.  That is, this exception is applied only for a
> single stereo-to-mono mix route, not for M-to-N mixing.
>

It seem that I am wrong after reconsidering this case

https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1432347

It is strange that a four channels codec has three audio outputs as the
datasheet only have two DAC

Codec: Realtek ALC272
Address: 1
AFG Function Id: 0x1 (unsol 1)
Vendor Id: 0x10ec0272
Subsystem Id: 0x17aac004
Revision Id: 0x100001
No Modem Function Group found
Default PCM:
    rates [0x560]: 44100 48000 96000 192000
    bits [0xe]: 16 20 24
    formats [0x1]: PCM
Default Amp-In caps: N/A
Default Amp-Out caps: N/A
State of AFG node 0x01:
  Power states:  D0 D1 D2 D3 CLKSTOP
  Power: setting=D0, actual=D0
GPIO: io=2, o=0, i=0, unsolicited=1, wake=0
  IO[0]: enable=1, dir=1, wake=0, sticky=0, data=1, unsol=0
  IO[1]: enable=0, dir=0, wake=0, sticky=0, data=0, unsol=0
Node 0x02 [Audio Output] wcaps 0x41d: Stereo Amp-Out
  Control: name="Bass Speaker Playback Volume", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Amp-Out caps: ofs=0x40, nsteps=0x40, stepsize=0x03, mute=0
  Amp-Out vals:  [0x2c 0x2c]
  Converter: stream=0, channel=0
  PCM:
    rates [0x560]: 44100 48000 96000 192000
    bits [0xe]: 16 20 24
    formats [0x1]: PCM
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
Node 0x03 [Audio Output] wcaps 0x41d: Stereo Amp-Out
  Control: name="Speaker Playback Volume", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Device: name="ALC272 Analog", type="Audio", device=0
  Amp-Out caps: ofs=0x40, nsteps=0x40, stepsize=0x03, mute=0
  Amp-Out vals:  [0x2c 0x2c]
  Converter: stream=0, channel=0
  PCM:
    rates [0x560]: 44100 48000 96000 192000
    bits [0xe]: 16 20 24
    formats [0x1]: PCM
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
Node 0x04 [Audio Output] wcaps 0x41d: Stereo Amp-Out
  Control: name="Headphone Playback Volume", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Amp-Out caps: ofs=0x40, nsteps=0x40, stepsize=0x03, mute=0
  Amp-Out vals:  [0x2c 0x2c]
  Converter: stream=0, channel=0
  PCM:
    rates [0x560]: 44100 48000 96000 192000
    bits [0xe]: 16 20 24
    formats [0x1]: PCM
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0