Lapdock HDMI audio - Atrix 4G Q&A, Help & Troubleshooting

Hello all,
I'm trying to use a Lapdock as an HDMI screen (there are a few threads about this, for example ), and the video part works fantastically. However, I can't seem to get an audio to play from the HDMI input on the Lapdock. I've tried a number of HDMI sources that supply audio with the video, and while the audio works on other HDMI monitors, the Lapdock doesn't produce any sound.
Does anyone know if I need to do something special to the Lapdock or the connector in order to get audio over HDMI?
Thanks,
Allan

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I could be wrong, but I don't think the lapdock uses audio over HDMI. I think it uses audio over the microUSB. I base this on how the other two docks I have work (both the car dock and MM dock).

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Wrong, the lapdock does use hdmi audio. same with the dock.

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callen81 said:
Wrong, the lapdock does use hdmi audio. same with the dock.
Click to expand...
Click to collapse
Doesn't the car dock use audio over usb?

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Everything I could find thus far suggests that the audio is over HDMI (for example, setting up the audio from a Raspberry Pi to go over HDMI as described - raspberry org/phpBB3/viewtopic.php?f=63&t=6747&p=86484 - about halfway down the page - "Mon May 28, 2012 4:33 pm". For for not providing a direct link - not enough karma on the forum to allow that yet!).
So it seems like it should be as simple as plugging in the HDMI, but that's no working for me. I might try plugging in a USB device as well and seeing that triggers something that will bring the HDMI audio up, but if anyone has any suggestions, I'm all ears!
Allan

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The car dock is over USB but its not done digitally. Its just a break out cable. I've had my Xbox/ps3 working with the lapdock.
Sent from my SGH-I747 using xda premium

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It should work
allanj said:
Hello all,
I'm trying to use a Lapdock as an HDMI screen (there are a few threads about this, for example ), and the video part works fantastically. However, I can't seem to get an audio to play from the HDMI input on the Lapdock. I've tried a number of HDMI sources that supply audio with the video, and while the audio works on other HDMI monitors, the Lapdock doesn't produce any sound.
Does anyone know if I need to do something special to the Lapdock or the connector in order to get audio over HDMI?
Thanks,
Allan
Click to expand...
Click to collapse
It works ok on my lapdock with both stock and custom ROM's (I was surprised to find the lapdock has two small speakers built in).
Unfortunately I can't think of any way you could test the speakers on the lapdock to see if they are working.

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So if the Lapdock uses HDMI for audio, then what kind of circuit is in there decoding the audio for those speakers? Not the typically higher cost decoders found in TVs or electronics shops, there's not eeven nough room inside the lapdock for those.
So what is working that magic? Anyone?

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Dock's audio
Dock's audio didn't work for me when I use custom ROM CM10.1, the audio out from the phone instead the output of dock.
Anyone know if have some workaround of this?

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vhcolombo said:
Dock's audio didn't work for me when I use custom ROM CM10.1, the audio out from the phone instead the output of dock.
Anyone know if have some workaround of this?
Click to expand...
Click to collapse
what kernel are you using?
Sent from my MB860 using xda app-developers app
---------- Post added at 11:20 AM ---------- Previous post was at 10:40 AM ----------
vhcolombo said:
Dock's audio didn't work for me when I use custom ROM CM10.1, the audio out from the phone instead the output of dock.
Anyone know if have some workaround of this?
Click to expand...
Click to collapse
if you're using a 3.1.10 kernel, hdmi not supported.
Sent from my MB860 using xda app-developers app

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palmbeach05 said:
what kernel are you using?
Sent from my MB860 using xda app-developers app
---------- Post added at 11:20 AM ---------- Previous post was at 10:40 AM ----------
if you're using a 3.1.10 kernel, hdmi not supported.
Sent from my MB860 using xda app-developers app
Click to expand...
Click to collapse
Yes the kernel is 3.1.10.
I think you have reason, so I can't use my dock

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vhcolombo said:
Yes the kernel is 3.1.10.
I think you have reason, so I can't use my dock
Click to expand...
Click to collapse
Its been discussed thoughrouly on the kernel dev threads and is stated in the what works/what doesn't work list. hdmi is not something required to make the phone stable, therefore its disabled and on the back burner for now. plus there are driver issues.
Sent from my MB860 using xda app-developers app

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palmbeach05 said:
Its been discussed thoughrouly on the kernel dev threads and is stated in the what works/what doesn't work list. hdmi is not something required to make the phone stable, therefore its disabled and on the back burner for now. plus there are driver issues.
Sent from my MB860 using xda app-developers app
Click to expand...
Click to collapse
Do you know if in the CM10 by Epinter the audio is working in the dock?
The kernel is 2.6.32.60
Thanks!!

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vhcolombo said:
Do you know if in the CM10 by Epinter the audio is working in the dock?
The kernel is 2.6.32.60
Thanks!!
Click to expand...
Click to collapse
It should work since its a non 3.1.10 kernel

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palmbeach05 said:
It should work since its a non 3.1.10 kernel
Click to expand...
Click to collapse
Ok, I will try this ROM

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lapdock does use the hdmi for audio. I have rpi 2 b. and two micro sd cards, one with kodi, and the other with debian/Jessie. im a noob at this, so I don't know all the different files in them. but when I use the one with kodi, I have sound through the lapdock. when I use the one with debian/Jessie no sound. however if I connect the pi (with debian/Jessie) to my vizio smart tv through hdmi I do have sound. I don't know if this helps.... and if some one could explain this that would help both of us.