ANNOUNCE: NVIDIA HDMI audio documentation

ANNOUNCE: NVIDIA HDMI audio documentation

[Stephen Warren]

I have written a document re: how to understand and trouble-shoot issues
with audio-over-HDMI on NVIDIA GPUs. It's available at:

ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html

The intent is to provide all the support information I've given various
people on support forums in a centralized place.

Hope this helps!

-- 
nvpublic

Re: ANNOUNCE: NVIDIA HDMI audio documentation

[Anssi Hannula]

On 04.02.2011 00:37, Stephen Warren wrote:
> I have written a document re: how to understand and trouble-shoot issues
> with audio-over-HDMI on NVIDIA GPUs. It's available at:
> 
> ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html
> 
> The intent is to provide all the support information I've given various
> people on support forums in a centralized place.
> 
> Hope this helps!

A nice document, thanks :)

A couple of comments:

> Early chipsets (ION an earlier) do not support PD or ELD information. In
> this case, the ALSA driver assumes that a monitor is always attached,
> and supports "basic audio” (stereo 16-bit PCM only).

The ALSA driver actually assumes that the monitor supports everything.

> 10.3. Under-Enumeration of Logical Devices

This section misses one patch:
http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=e6d5dcf1f625984605d362338d71162de45a6c60

> 12.4. Verify Your ELD Is Valid

This section has "44100 48000 88200" multiple times. Maybe one should
mention that those are currently shown incorrectly (as per "[alsa-devel]
HDA - hdmi_show_short_audio_desc puts wrong rates in eld#N"). Maybe also
in chapter 10, though it is a very minor issue (it just affects the
display, not the actual used values).

-- 
Anssi Hannula

Re: ANNOUNCE: NVIDIA HDMI audio documentation

[Stephen Warren]

Anssi Hannula wrote:
> On 04.02.2011 00:37, Stephen Warren wrote:
> > I have written a document re: how to understand and trouble-shoot issues
> > with audio-over-HDMI on NVIDIA GPUs. It's available at:
> >
> > ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html
>
> A nice document, thanks :)
>
> A couple of comments:

Thanks very much for the feedback.

>...
> > 12.4. Verify Your ELD Is Valid
> 
> This section has "44100 48000 88200" multiple times.

I'm having trouble finding this. Can you quote a bit more text to highlight
exactly where/what the problem is?

> Maybe one should mention that those are currently shown incorrectly (as
> per "[alsa-devel]  HDA - hdmi_show_short_audio_desc puts wrong rates in
> eld#N").

Am I correct that this isn't patched yet? I couldn't see anything that
touched this in the git log, nor any following to this email:

http://mailman.alsa-project.org/pipermail/alsa-devel/2011-January/035557.html

Thanks again.

--
nvpublic

Re: ANNOUNCE: NVIDIA HDMI audio documentation

[Anssi Hannula]

On 07.02.2011 19:39, Stephen Warren wrote:
> Anssi Hannula wrote:
>> On 04.02.2011 00:37, Stephen Warren wrote:
>>> I have written a document re: how to understand and trouble-shoot issues
>>> with audio-over-HDMI on NVIDIA GPUs. It's available at:
>>>
>>> ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html
>>
>> A nice document, thanks :)
>>
>> A couple of comments:
> 
> Thanks very much for the feedback.
> 
>> ...
>>> 12.4. Verify Your ELD Is Valid
>>
>> This section has "44100 48000 88200" multiple times.
> 
> I'm having trouble finding this. Can you quote a bit more text to highlight
> exactly where/what the problem is?

The examples have:
> sad0_rates          [0xe0] 44100 48000 88200
> HDMI: supports coding type LPCM: channels = 2, rates = 44100 48000 88200, bits = 16 20

While you are not claiming they are correct, it would probably be best
to mention that in the text (and/or in the issues chapter).

>> Maybe one should mention that those are currently shown incorrectly (as
>> per "[alsa-devel]  HDA - hdmi_show_short_audio_desc puts wrong rates in
>> eld#N").
> 
> Am I correct that this isn't patched yet? I couldn't see anything that
> touched this in the git log, nor any following to this email:
> 
> http://mailman.alsa-project.org/pipermail/alsa-devel/2011-January/035557.html

Yes, the issue is not yet fixed.

I planned to provide a patch but I haven't had the time to do it yet
after all.

> Thanks again.


-- 
Anssi Hannula

Re: ANNOUNCE: NVIDIA HDMI audio documentation

[Stephen Warren]

Anssi Hannula wrote at Monday, February 07, 2011 1:49 PM:
> On 07.02.2011 19:39, Stephen Warren wrote:
> > Anssi Hannula wrote:
> >> On 04.02.2011 00:37, Stephen Warren wrote:
> >> ...
> >>> 12.4. Verify Your ELD Is Valid
> >>
> >> This section has "44100 48000 88200" multiple times.
> >
> > I'm having trouble finding this. Can you quote a bit more text to
> > highlight exactly where/what the problem is?
> 
> The examples have:
> > sad0_rates          [0xe0] 44100 48000 88200
> > HDMI: supports coding type LPCM: channels = 2, rates = 44100 48000 88200, bits = 16 20

Ah! Now that I read this again, I see what you mean:

I thought you mean the text was incorrectly duplicated. You were in fact
simply pointing out the fact that the text you quoted (which happens to
appear a couple of times) was wrong due to the issue with rate printing.

Thanks.

-- 
nvpublic