Slow HDMI audio clock in pandaboard rev A4 using Ubuntu 11.10 Oneiric Ocelot binaries ?

[Joaquin Castellanos]

Hi all,

I noticed a curious behavior when I try to run some AV-clips in my rev A4 pandaboard through the HDMI output.
Seems that the audio clock used by the HDMI is running at only half frequency, making any given videoclip to take the double of time for its completion (like in slow motion).    ... The good news is that the video frames are in sync with the audio buffers.    =)

Using the same kernel / filesystem (  3.1.0-1282-omap4  +  Ubuntu 11.10 Oneiric Ocelot binaries from http://omappedia.org/wiki/Ubuntu_Pre-Built_Binaries + ubuntu-omap4-extras), this time with a pandaboard rev A3, I found no signs of this behavior. The AV playback is completed at normal speed without problems.

Therefore I assume that some change between HW revisions affected the HDMI clock configuration.

Ricardo Neri kindly provided some test lines to help to determine if the issue was only present on the HDMI audio output
----------------
<Analog audio output>
time aplay -D hw:0,0 -v Roland-GR-1-Trumpet-C5.wav
...
real        0m3.269s
user        0m0.078s
sys        0m0.047s

<HDMI audio output>
time aplay -D hw:1,0 -v Roland-GR-1-Trumpet-C5.wav
...
real        0m6.370s
user        0m0.000s
sys        0m0.086s
----------------

Redirecting the audio to the analog output makes the AVplayback to work fine in both boards.

Please let me know if you also noticed this issue or if there is any workaround already available.

Best regards
Joaquin Castellanos

[Neri, Ricardo]

Hi,

Joaquin mentions he observes the issue in panda rev A4 (which has a 4430 ES2.3 processor). Recently, some patches to control how the ACR packets are sent (http://www.spinics.net/lists/linux-omap/msg64302.html). These patches went upstream on K3.4. However, the ubuntu kernel may have taken earlier. As these patches behave differently according to the silicon revision, they may provide insight on the issue Joaquin observes.

If someone could point me to the kernel repository used in the 10.10 kernel, I could try to take a look. Unfortunately, I am out of the office this week; I could do some quick tests the next week.

thanks,

Ricardo

---

From: Joaquin Castellanos [jcastel...@gmail.com]
Sent: Tuesday, April 10, 2012 3:00 PM
To: panda...@googlegroups.com
Cc: Neri, Ricardo
Subject: Slow HDMI audio clock in pandaboard rev A4 using Ubuntu 11.10 Oneiric Ocelot binaries ?

[Nicolas Dechesne]

On Wed, Apr 11, 2012 at 12:00 AM, Neri, Ricardo <ricard...@ti.com> wrote:
> If someone could point me to the kernel repository used in the 10.10 kernel,
> I could try to take a look. Unfortunately, I am out of the office this week;
> I could do some quick tests the next week.

here is the git tree/branch to use:

http://dev.omapzoom.org/?p=integration/kernel-ubuntu.git;a=shortlog;h=refs/heads/ti-ubuntu-3.1-1282

and instructions to build:

http://omappedia.org/wiki/Ubuntu_kernel_for_OMAP4

[E V]

Recently I posted about problems with HDMI audio. I solved it in a RevA2 board, but now in my RevA4 there is the same problem Joaquin Castellanos reports.

I am using 11.10 + omap4-extras, and my software uses gstreamer (with accelerated hardware) to play videos.

2012/4/11 Nicolas Dechesne <nde...@gmail.com>

[E V]

Any updates?

2012/4/12 E V <evia...@gmail.com>

[Joaquin Castellanos]

Hi Nicolas

Pandaboard ES rev. B1 has also the same HDMI audio/clock problem with Ubuntu 11.10.  Can we expect a patch soon?

Regards
Joaquin Castellanos