deymious
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problems setting raspberry pi up with lapdock 500

Sun Jun 02, 2013 2:09 am

hey all,

before we begin. let me tell you that i've googled everything and tried so many different forums but nothing has solved my problem. so this is the issue, i'm trying to hook up my raspberry pi to the motorola lapdock 500. i know the rpi works and the SD cards work (i've tried both raspbian and xbmc) but didn't have any luck with it working on the rpi, but it worked on the tv so i know the SD cards/rpi is functional. I also know the lapdock works because I can hook up my droid bionic to it and its fine.

I have the revision 2 rpi so according to a bunch of different sources, I don't need to hook it up to a power outlet when its hooked up to the lapdock, i can just charge it with a male to male usb cable from the rpi to the lapdock. Then I have a small adapter that converts the male micro hdmi on the lapdock to a female micro hdmi and then subsequently a cable connecting it to the rpi.

i've also tried connecting the rpi power cable to the lapdock because Ive read that that might be a reason why its not turning on. I've tried connecting both the power cable and the usb cable as well as the hdmi, but still nothing.

Is there something unique I'm supposed to do to set up raspbian/xbmc to run on the rpi from the lapdock? Or should it just work after I installed it on them. I've interchanged all the cables except the little adapter that helps me connect the rpi hdmi cable to the lapdock. Would this be the culprit?

Just need some advice because I've been working on this on and off again for almost a year. Just let me know if you need any more clarification. Thank you!

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johnbeetem
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Re: problems setting raspberry pi up with lapdock 500

Sun Jun 02, 2013 4:44 am

There's been a lot posted here and elsewhere about the Motorola Atrix Lapdock. I expect the Lapdock 500 behaves similarly.

A good starting point is the Atrix Lapdock section at the RasPi Hardware Wiki: http://elinux.org/RPi_Screens#Motorola_Atrix_Lapdock
It summarizes the most important Lapdock lore, and has links to important discussions and 'blog posts.

In your particular case, if the Lapdock is not powering on at all I suspect that your HDMI A male to Micro HDMI D male cable is missing the DDC/CEC ground wire which Lapdock uses to detect that a phone is plugged into it. There's a summary of this issue at the Wiki. I had exactly this problem when I first tried to get my Lapdock working and tracked it down using perseverance and luck: http://www.element14.com/community/grou ... ork-around

[I'm assuming you've already made sure your Lapdock was either plugged in (with charging LED blinking) or batteries were charged.]

deymious
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Re: problems setting raspberry pi up with lapdock 500

Tue Jun 04, 2013 4:03 pm

Hey man thanks for the response. Yeah I made sure the lapdock was charged and I also tried it while charging, it still wouldn't turn on. I saw the link you sent me but doing that stuff is a bit past my skill level heh, so is there simple another cable I can get that will definitely have the DDC/CEC ground wire? Because I rather shell out some money for that when its worked for others then try and go tinkering and FUBAR. Thanks for all the advice, really appreciate it.

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johnbeetem
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Re: problems setting raspberry pi up with lapdock 500

Wed Jun 05, 2013 4:24 am

deymious wrote:Hey man thanks for the response. Yeah I made sure the lapdock was charged and I also tried it while charging, it still wouldn't turn on. I saw the link you sent me but doing that stuff is a bit past my skill level heh, so is there simple another cable I can get that will definitely have the DDC/CEC ground wire? Because I rather shell out some money for that when its worked for others then try and go tinkering and FUBAR. Thanks for all the advice, really appreciate it.
I've had good luck with a (links follow) Kmashi 30 cm Micro HDMI female to Micro HDMI male cable plus a Micro HDMI female to full-size HDMI male adapter. This provides a more robust connection at the Lapdock end than those Micro HDMI female-to-female adapters. 30 cm is nice and short for a clean set-up.

gregeric
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Re: problems setting raspberry pi up with lapdock 500

Wed Jun 05, 2013 1:11 pm

Apparently the Lapdock 500 fails to work with anything but the intended Motorola devices; unlike the Atrix Lapdock it cannot be used as an HDMI monitor for the rPi. Or so user robpol86 has reported here on this forum and on his blog.

deymious
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Re: problems setting raspberry pi up with lapdock 500

Wed Jun 05, 2013 2:25 pm

thank you both for your responses. I will try and order these two items and see how well it works for me.

and thats weird (altho it would make sense given what I have seen) that the lapdock 500 won't work with the rpi. how can the lapdock tell that its not a motorola device attached to it but rather a raspberry pi, if you're using both of the connectors?

gregeric
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Re: problems setting raspberry pi up with lapdock 500

Wed Jun 05, 2013 3:12 pm

http://www.youtube.com/watch?v=zCxTTrTZSSM

Maybe you can play with the Pi's hdmi cec options in config.txt to mimic a droid phone & overcome this problem? Just a hunch.

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heatfanjohn
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Re: problems setting raspberry pi up with lapdock 500

Fri Jun 28, 2013 6:03 pm

by johnbeetem » Wed Jun 05, 2013 4:24 am wrote:

I've had good luck with a (links follow) Kmashi 30 cm Micro HDMI female to Micro HDMI male cable plus a Micro HDMI female to full-size HDMI male adapter. This provides a more robust connection at the Lapdock end than those Micro HDMI female-to-female adapters. 30 cm is nice and short for a clean set-up.
I just ordered your suggested HDMI cable and adapter as the ones that I am currently using do not cause my Altrix Lapdock to "turn on" when my Pi is connected. The cable and/or adapter that I'm currently using must not pass the DDC/CEC/HEC ground that you identified in your excellent Element14 posting.

AmazingPants
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Re: problems setting raspberry pi up with lapdock 500

Wed Jul 17, 2013 11:06 pm

deymious,
What about your progress with lapdock 500? Does it work with RPi now?

deymious
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Re: problems setting raspberry pi up with lapdock 500

Wed Jul 24, 2013 4:18 pm

hey.

cannot say i've had any true luck. had it turn on for a brief second so that it was flashing on the screen (a white light) but after that nothing and thus i kinda gave up hope...

trying to see what else i can do with the lapdock 500 before i sell it. anyone got any good ideas? :roll:

cookin1983
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Re: problems setting raspberry pi up with lapdock 500

Sun Aug 04, 2013 2:05 am

I made a little progress with my lapdock 500. Here is the video of what it does http://www.youtube.com/watch?v=VoXCR82RCWE. I set the hdmi settings in config.txt according to these instructions http://www.mobilewill.us/2012/10/raspbe ... pdock.html. It's so close I just don't know what i need to do to make it stay on for more than a few seconds.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Tue Aug 06, 2013 10:49 am

I have the same problem, except that the screen is not lighting up. The issue must be either that the lapdock is expecting a very particular hdmi signal from the razr, or it is sending a query down the usb and expecting something specific back. I do not have access to a Razr so it is hard to troubleshoot, but it can't be impossible to emulate a Razr on the Raspberry Pi if we knew what was missing.

cookin1983
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Re: problems setting raspberry pi up with lapdock 500

Tue Aug 06, 2013 8:00 pm

I have a RAZR, I just don't know what I need to do to get that info off of it.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Wed Aug 07, 2013 7:24 am

cookin1983 wrote:I have a RAZR, I just don't know what I need to do to get that info off of it.
I am no expert on mobile phones and hdmi, but probably a good place to find out more is with forums dealing with the RAZR and hdmi issues. We are both feeling around in the dark here, but since I don't have access to a RAZR I am at an even bigger disadvantage.

As a start, what does the RAZR list as it's hdmi spec (version, etc.), and next is there a file on the RAZR which sets up the hdmi preferences (I assume that you can get everything working with the RAZR). Also, just to eliminate the obvious, use as many of the cables and adapters between the RAZR and the 500 as possible (I realize that the Raspberry Pi has full size hdmi/USB as opposed to micro, but in case you have a reverse adapter handy to bring it down to micro again, give it a try [I ended up with a few extra adapters due to mistakes on specs :( ]) just to rule out cable issues.

Another area to look into (I will see what I can find here) is what information is sent down the hdmi interface in the initial negotiation (my computer knows a lot about any hdmi device I connect to it, so it must be querying the device and getting specs back, so presumably the 500 is doing something analogous).

A few things to start with.

btw, I almost feel like giving up on the 500 and going for an Atrix 100, except that I touch type, and I would love a decent keyboard.

cookin1983
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Re: problems setting raspberry pi up with lapdock 500

Wed Aug 07, 2013 11:31 pm

sansevero wrote:
cookin1983 wrote:I have a RAZR, I just don't know what I need to do to get that info off of it.
I am no expert on mobile phones and hdmi, but probably a good place to find out more is with forums dealing with the RAZR and hdmi issues. We are both feeling around in the dark here, but since I don't have access to a RAZR I am at an even bigger disadvantage.

As a start, what does the RAZR list as it's hdmi spec (version, etc.), and next is there a file on the RAZR which sets up the hdmi preferences (I assume that you can get everything working with the RAZR). Also, just to eliminate the obvious, use as many of the cables and adapters between the RAZR and the 500 as possible (I realize that the Raspberry Pi has full size hdmi/USB as opposed to micro, but in case you have a reverse adapter handy to bring it down to micro again, give it a try [I ended up with a few extra adapters due to mistakes on specs :( ]) just to rule out cable issues.

Another area to look into (I will see what I can find here) is what information is sent down the hdmi interface in the initial negotiation (my computer knows a lot about any hdmi device I connect to it, so it must be querying the device and getting specs back, so presumably the 500 is doing something analogous).

A few things to start with.

btw, I almost feel like giving up on the 500 and going for an Atrix 100, except that I touch type, and I would love a decent keyboard.
Just for fun I tried connecting the micro usb directly to the razr and just trying to use the lapdock as a monitor but it didn't work.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Fri Aug 09, 2013 9:30 am

There is a video on the internet of someone doing more or less the same thing with the same result. Odds are, therefore, that the issue has something to do with hdmi.

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Davespice
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Re: problems setting raspberry pi up with lapdock 500

Fri Aug 09, 2013 11:21 am

If its any help, here is my guide on making a custom cable which should do it.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Fri Aug 09, 2013 4:06 pm

I think there is a seperate issue with the lapdock 500 pro that your cable solution would not address. For example, while I do not have a lapdock 100, I believe that if you connect an hdmi cable to it from your computer, it will act as an additional monitor (please correct me if this is not true). The 500 does not behave this way (at least I have yet to find someone who has successfully done so--definitely correct me if this is true as it would go a long way to solving the mystery). The 500 seems to engage in some manner of check, most likely on the hdmi connection, which tries to determine if a RAZR is connected, and if the check fails, shuts down after a few seconds (and won't restart for at least 10 or 15 seconds).
Short of a Motorla lapdock engineer who could answer the question, we probably need to find someone with more experience of the hdmi 'handshake' that starts up a connection, and/or someone who is familiar with how the digital rights management on hdmi operates, which may be another route to implementing a check.
It is certainly a pain that Motorola decided to make the 500 less flexible, but I have heard it suggested that the additional equipment on the 500 posed compatibility issues that were not there on the 100, so this was an attempt to get a better 'user experience'.

cookin1983
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Re: problems setting raspberry pi up with lapdock 500

Sun Aug 11, 2013 8:00 pm

Last night I plugged the pi into it's own power but connected the usb and hdmi into the lapdock. After the lapdock turned on and off I plugged the pi into my tv. The keyboard and the track pad worked worked great. It is driving me insane that the dang display won't stay on but this test makes me think I can rule out the display power being controlled by the usb.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Mon Aug 12, 2013 7:38 am

Great idea for an experiment! I will try that myself later today to see if I get the same results.
A quick question. When your screen comes on for a few seconds, it is showing the ras pi output, or is it blank or showing something else? With mine the screen never lights up, so I have been unable to tell.
If the rest of the dock is working, then, hopefully, we have narrowed it down to the powering up of the dock and the screen in particular (I am guessing that the keyboard and track pad were being powered by the ras pi and not from the internal battery).
My guess is it is still an issue with how ras pi handles the hdmi handshake rather than a hardware issue.

cookin1983
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Re: problems setting raspberry pi up with lapdock 500

Mon Aug 12, 2013 12:40 pm

When the screen comes on it does show the pi's desktop. I don't think the the dock is getting power from the pi because the red wire doesn't go to the usb side of the adapter I made. The biggest frustration with this whole thing is that the dock won't react the same way every time. This is the process that I've had the most luck with.
1. Open the dock.
2. Plug the pi into the wall.
3. Connect the hdmi and usb to the pi.
4. Plug the hdmi into the dock.
5. Connect the usb to the dock.
6. Unplug the hdmi from the pi and reconnect it.
If the screen turns on and off then you are good to connect to another display. I did set my config.txt file with
hdmi_force_hotplug=1
and
hdmi_drive=2
uncommented.
This only works about 5%-10% of the time so you may have to repeat 4-6 several times.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Mon Aug 12, 2013 7:21 pm

Well, I tried to duplicate your results with no luck. The only response I get when connecting the pi to the dock is that led next to the dock button flickers red for a second. When connected to a TV I get the pi desktop, but no response from the trackpad or keyboard.
I also tried a long list of alternative settings on the config.txt file including the following:
sdtv_aspect
sdtv_disable_colourburst
hdmi_ignore_edid
hdmi_force_edid_audio
avoid_edid_fuzzy_match
hdmi_ignore_cec
hdmi_ignore_hotplug
hdmi_drive
hdmi_group
hdmi_mode
test_mode
framebuffer_depth
all to no avail. I sort of wish I did have a RAZR handy somewhere just to prove to myself that the lapdock is not DOA.

cookin1983
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Re: problems setting raspberry pi up with lapdock 500

Mon Aug 12, 2013 7:39 pm

The only way to get the keyboard and mouse on the dock to work is if the screen turns on then off. I don't know why the dang dock won't act the same every time you do something to it. I think that may be more irritating than it not working at all. My uncle has an oscilloscope I may be able to use to see what type of signal my RAZR is putting out through the hdmi. Outside of that I don't know what else to do.

sansevero
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Re: problems setting raspberry pi up with lapdock 500

Mon Aug 12, 2013 7:55 pm

This really is puzzling. At some point I am going to end up opening up the dock in hopes of making some sense of it there, but it really should not be necessary. I am not sure an oscilloscope will be much help as the communication will likely be digital. If we could come up with any other device that would get the screen to work, we might have a clue.


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