Available controls in alsamixer defending on UEFI firmware?

[Klaus Siegesleitner]

Hi all!

The initial UEFI Firmware of my Minnow-Board was 0.94.
Booting with this firmware and starting alsamixer, I got a bunch of available controls like

• Master
• PCM
• Line
• CD
• S/PDIF
• ... (at least 3 more)
  

After a neccessary firmware update to 1.0 I was surprised when I started alsamixer again - I now only have:

• Master
• Line
• S/PDIF
• S/PDIF Default PCM

So, do the available controls depend on the UEFI firmware?

I also have connected a CD-ROM drive - so how can I play audio from CD and adjust its volume...?

Thanks a lot
klausix!

[Scott Garman]

On 01/22/2014 01:30 PM, Klaus Siegesleitner wrote:
> Hi all!
>
> The initial UEFI Firmware of my Minnow-Board was 0.94.
> Booting with this firmware and starting alsamixer, I got a bunch of
> available controls like
>

> * Master
> * PCM
> * Line
> * CD
> * S/PDIF
> * ... (at least 3 more)

>
> After a neccessary firmware update to 1.0 I was surprised when I started
> alsamixer again - I now only have:
>

> * Master
> * Line
> * S/PDIF
> * S/PDIF Default PCM

>
> So, do the available controls depend on the UEFI firmware?
>
> I also have connected a CD-ROM drive - so how can I play audio from CD
> and adjust its volume...?
>
> Thanks a lot
> klausix!

Hi Klaus,

I checked with a firmware engineer and obtained this response:

"The HD audio verb table was updated to properly describe the
connections to the codec. Only Audio In and Audio Out via the blue and
green jacks were specified."

"Older CD-ROM/DVD drives used an analog audio path with a separate
connector to the motherboard that fed into the codec. This connection
does not exist on the Minnow board. Playing CDs requires directly
reading and processing the digital data and outputting that from the CPU
through the HD audio controller and audio codec to the audio output
jack. Volume would be controlled by the level of the output volume for
the audio output jack. Some programs may not be capable of this
operation and instead expect to have the CD/DVD drive provide audio in
analog form directly to an input on the audio codec. In this latter
case there would be a CD volume control to adjust the CD's input volume
to the mixer in the audio codec."

So it sounds like the newer firmware more accurately represents the
audio capabilities of the board by eliminating the ones that were not
available.

Scott

--
Scott Garman
Embedded Linux Engineer - Yocto Project
Intel Open Source Technology Center