[alsa-devel] [RFC] Fix for conflict of HDMI and SPDIF IEC958 controls

[Raymond Yau]

2012-10-12 下午11:19 於 "Takashi Iwai" <tiwai at suse.de> 寫道：
>
> Hi,
>
> there is a long-standing problem in HD-audio regarding IEC958
> controls.  When both an SPDIF and an HDMI are created on the same
> card (e.g. one from analog codec and one from graphics chip), the
> driver assigns the IEC958 controls just with new indices, 0, 1, 2...
>
> The problem is that there is no way to connect between this index and
> the actual PCM device.  Currently, alsa-lib HDA-Intel.conf has a fixed
> configuration:
>   spdif  -> IEC958 xxx index=0, PCM dev=1
>   hdmi,0 -> IEC958 xxx index=0, PCM dev=3
>   hdmi,1 -> IEC958 xxx index=1, PCM dev=7
>   hdmi,2 -> IEC958 xxx index=2, PCM dev=8
>   hdmi,3 -> IEC958 xxx index=3, PCM dev=9
>
> So obviously spdif and the first hdmi conflict.
>
> Basically this can be fixed by reassigning each IEC958 control with
> the same device number corresponding to the PCM device.  That is, for
> SPDIF, assign a control element with device=1, for HDMI,
> device=3,7...
> However, this obviously breaks the old configuration unless user
> upgrades the alsa-lib configuration.  Thus this is no-go.
>
> Now here is a compromise: the IEC958 control for SPDIF is reassigned
> to device=1 *only* when SPDIF and HDMI coexist.  Since the
> configuration is anyway broken as is now in such a case, it's no big
> deal to fix one side in an incompatible way.  (The reason why SPDIF
> is re-assigned is that I guess majority of user require more HDMI than
> SPDIF in such a configuration.)
>
> In addition, we need a fix in alsa-lib.  Also not for breaking the
> compatibility with older kernel, we need some fallback check.  I did a
> quick hack to alsa-lib conf code and added "skip_rest" option to the
> hook element, so that only the first matching element is taken.

how about those hdmi jack and iec958 on ad1989b?

there is no device 3 but [Jack] SPDIF Out at Ext Rear and [Jack] Digital
Out at Int HDMI

**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 1: AD198x Digital [AD198x Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 2: AD198x Headphone [AD198x Headphone]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/995169/+attachment/3132070/+files/Card0.Codecs.codec.0.txt

Node 0x1b [Pin Complex] wcaps 0x40030d: Stereo Digital Amp-Out
  Control: name="IEC958 Playback Volume", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Amp-Out caps: ofs=0x27, nsteps=0x27, stepsize=0x05, mute=1
  Amp-Out vals:  [0x00 0x00]
  Pincap 0x00000010: OUT
  Pin Default 0x0145f1a0: [Jack] SPDIF Out at Ext Rear
    Conn = Optical, Color = Other
    DefAssociation = 0xa, Sequence = 0x0
    Misc = NO_PRESENCE
  Pin-ctls: 0x40: OUT
  Connection: 1
     0x02

Node 0x1d [Pin Complex] wcaps 0x40030d: Stereo Digital Amp-Out
  Control: name="HDMI Playback Volume", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Amp-Out caps: ofs=0x27, nsteps=0x27, stepsize=0x05, mute=1
  Amp-Out vals:  [0x27 0x27]
  Pincap 0x00000010: OUT
  Pin Default 0x1856f1b0: [Jack] Digital Out at Int HDMI
    Conn = Digital, Color = Other
    DefAssociation = 0xb, Sequence = 0x0
    Misc = NO_PRESENCE
  Pin-ctls: 0x40: OUT
  Connection: 1
     0x0b