BeagleBone Black rev C HDMI color issues (Debian wheezy 7.8)

[David Alston]

I have been having issues with my beaglebone black when connecting to a monitor over HDMI. Certain colors are missing from the output as shown in the attached images. From looking around it may be an issue with the sitara processor on the BB, possibly having to do with 16 vs 24 bit color. However I could not get a workaround form what I have come across. Has anyone else had similar problems? Ideas for a fix or solution? Any help would be greatly appreciated.

FullSizeRender is the test image on a windows machine, FullSizeRender2 is as it appears on the BB using Imagemagick.

Let me know if more information is required.

[Sean S]

You're right, it is to do with 16 vs 24 bit colour, see https://groups.google.com/d/topic/beagleboard/PjKwp6XCNnA/discussion for a fix that worked for me.

[David Alston]

I still have the same problem after adding that into xorg.conf. Putting the process I used here in case I screwed up:

sudo nano /etc/X11/xorg.conf

Then I made the changes and saved (Ctrl O) then exited (Ctrl X)

Then rebooted. I went to the desktop with no issues, but the color problem persists.

[William Hermans]

David,

Yes, others have experienced this problem. As I've seen a few post on similar subject over the past couple years. While I can not say 100% what will fix this issue for you, most of the posts I remember seeing seemed to be with reversed, or swapped colors.

So without remembering the exact details of every post. What I can do is perhaps help you, help yourself. If you go into the beagleboard.org google group, and refine your search by date. You should be able to find the posts I'm talking about. What exact keywords to search for . . . well that you'll have ot experiment with. Color will definitely be one of them. . .

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[David Alston]

I have been searching for a few days now. I have used the Beagleboard site, google groups for the beagleboard site, stackexchange etc. 

[William Hermans]

I have been searching for a few days now. I have used the Beagleboard site, google groups for the beagleboard site, stackexchange etc.

Ok well I seem to recall there is a way to set screen resolution, and bitdepth in uEnv.txt. Passed that I also seem to recall there is a login manager configuration file that needs to be configured properly in order for this to work. I know this is all rather vague, but that is the best I can personally do. As I have never had a need for hdmi output personally . . .

[William Hermans]

For what it is worth, and in case this might help. The screen resolution / bitdepth I mentioned in uEnv.txt is a kernel parameter. So if you happen across a post or article that mentions kernel params for screen resolution, etc. uEnv.txt is how the uboot passes kernel params to the kernel.

Or maybe I just confused the situation more ?

Example, examining /boot/uEnv.txt:
...
cmdline=quiet init=/lib/systemd/systemd
...

cmdline=

is where one would pass kernel parameters to the kernel. Using uboot on the beaglebone black.

[David Alston]

I am still having issues with the system. I have tried the fix listed by Sean S but that did not fix it unfortunately. Does anyone know a command or kernel update to force the colors to correctly render?

[David Alston]

Just wanted to update everyone here. Turns out it was a hardware problem on the Beaglebone black. Got a new one and had no color problems. Old one successfully sent out for RMA. Thanks for the help guys, turned out to be something fairly simple.