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

[Takashi Iwai]

At Mon, 15 Oct 2012 21:10:44 +0800,
Raymond Yau wrote:
> 
> > > > > > >
> > > > > > > how about those hdmi jack and iec958 on ad1989b?
> > > > > >
> > > > > > On AD codecs, all digital outputs are exposed as a single cloned
> > > > > > device with HDA_PCM_TYPE_SPDIF.
> > > > >
> > > > > how about ad1988b with nvidia codec ?
> > > >
> > > > Nvidia codec provides devices only with HDA_PCM_TYPE_HDMI, of course.
> > > >
> > > > > from user point of view , how can they differenitate hdmi jack is
> > > digital
> > > > > ouput and hdmi output ?
> > > >
> > > > The device 1 is from AD and the device 3 is from Nvidia codec, as you
> > > > can see below.  And this is exactly the case the conflict happens as I
> > > > mentioned in the original mail.
> > >
> > > will your fix change the spdif of  those motherboard with ad1988b which
> > > have iec958 but no hdmi jack ?
> >
> > It won't change anything unless both SPDIF and HDMI *devices* are
> > actually created.
> >
> >
> >
> > > > Which is connected to what output, you can't know exactly unless you
> > > > compare the obtained ELD.  The HD-audio spec isn't good enough to
> > > > identify the actual output.
> > >
> > > it seem that there is no presence detect on this codec
> >
> > ELD has nothing to do with the presence detect bit.
> >
> 
> ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html#_examples
> 
> 6.1.2. Chipset with 8-channel support, single stream
> 
> This configuration is used in MCP77, MCP78, MCP79, MCP7A, and ION.
> 
> In the case where multiple HDMI display connectors are present, the audio
> stream is broadcast to all HDMI connectors at once. A single ALSA device is
> exposed.
> 
> ELD and PD information is not available on these chipsets.
> 
> In these chipsets, the multiple 2-channel converters are aggregated by the
> ALSA driver and exposed as a single 8-channel device. Some chipsets support
> 2, or 8 channels (MCP77). Other chipsets support 2, 6, or 8 channels
> (MCP79).
> 
> id = 0x10de0002, .name = "MCP77/78 HDMI",    .patch = patch_nvhdmi_8ch_7x },
> 
> does it mean that this hdmi codec support 8 channels but no ELD info ?

Right.


Takashi