Viriiguy
Posts: 13
Joined: Sun Jul 17, 2016 2:26 pm

Overscan left and right not working.

Wed Sep 07, 2016 11:15 am

Hey gang,

I have a Pi3 running Raspbian. I recently purchased a 7" Touchscreen with a native resolution of 800x480. I went into /boot/config.txt and set my resolution to 800x480 but had black bars all the way around. So I uncommented DisableOverscan=1 and that fixed the top and bottom, but the sides each have about 1/4" wide black bars still. So I uncommented the Overscan settings as well and began playing with them.

I did check, as mine is a NOOBS install, but I do not have the overscan settings on the bottom of the file. They are only in there once. So we can rule that out. No matter what I set the overscan for left and right to, it never ever changes after a reboot. The bars stay 1/4" wide on each side. I have gone from 100 to -100000 with zero change.
But if I edit the top and bottom overscan settings, those work.

Any thoughts?
Thanks!

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topguy
Posts: 6620
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Location: Trondheim, Norway

Re: Overscan left and right not working.

Wed Sep 07, 2016 11:19 am

Could use some more info about the screen ? What is the interface, HDMI or something else ?

Can you run "omxplayer" and play some 19:6 video and see if you still have the black bars on that video or not.

Viriiguy
Posts: 13
Joined: Sun Jul 17, 2016 2:26 pm

Re: Overscan left and right not working.

Wed Sep 07, 2016 11:23 am

It is connected via HDMI. This is the screen that I bought.
http://www.ebay.com/itm/2DIN-IN-DASH-7- ... 1482589365

I will try playing a video, but that won't be until later today, when I have it on an internet connection. Right now I am at work, playing with it on my desk. But the internet is pretty locked down.

Viriiguy
Posts: 13
Joined: Sun Jul 17, 2016 2:26 pm

Re: Overscan left and right not working.

Wed Sep 07, 2016 11:25 am

Ok, weird... It is only the desktop. When I launch KODI, it fills the screen properly.

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topguy
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Joined: Tue Oct 09, 2012 11:46 am
Location: Trondheim, Norway

Re: Overscan left and right not working.

Wed Sep 07, 2016 1:22 pm

Its not really that surprising, but it also means that the overscan parameters doesnt work well for that resolution.
There are two kinds of framebuffers, one used by Kodi and other software using GPU, and the other is a linux framebuffer which is used by the console and X-Windows.
The framebuffers that Kodi uses ignores all system overscan parameters and will fill the whole screen anyway.

Did you have to set the resolution in config.txt for the screen to work, what happens if you let the Pi figure out the format itself ?

Viriiguy
Posts: 13
Joined: Sun Jul 17, 2016 2:26 pm

Re: Overscan left and right not working.

Wed Sep 07, 2016 2:49 pm

According to the instructions, in order to be able to configure the touchscreen, which I have not done yet... Yes, I have to set the frame buffers. When I let Pi figure it out for itself, it wants to run at 1920x1080.. Which the screen WILL support, but the native resolution is 800x480. And at 1920, I can't read anything.

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DougieLawson
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Re: Overscan left and right not working.

Wed Sep 07, 2016 7:42 pm

If you've installed Raspbian with NOOBS you have the tvservice command.

tvservice -m CEA; tvservice -m DMT
Run that command and look at the output. Is there a mode line for 800x480 returned.

Once you know the mode number and whether it's CEA or DMT we can add a couple of lines to /boot/config.txt to force your RPi to always run in that mode. Something like

Code: Select all

hdmi_mode=2
hdmi_group=4
See https://www.raspberrypi.org/documentati ... fig-txt.md for details
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Viriiguy
Posts: 13
Joined: Sun Jul 17, 2016 2:26 pm

Re: Overscan left and right not working.

Thu Sep 08, 2016 8:45 am

There does not seem to be a mode in that resolution. However, it shouldn't be too big of a deal. Once I have everything setup the way I want, it will launch everything from KODI anyway. But thank you!

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