Mark a portion of the screen as unusable

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Problem :

I have a laptop of which a large part of the screen is broken (shows garbage). Fortunately the broken area is a clean rectangle, the bottom 1/3 of the screen or so.

The laptop is running Ubuntu 8.04, but I plan to reinstall it with 10.10. The graphics are provided by an Intel 915GM or something in that direction.

Knowing this, do you know of a way to tell the system about the broken part of the screen, so it will simply not use it? I don’t really care whether it’s done at the hardware, X or window manager level, though as low as possible is preferred.

Solution :

It’s possible but it’s gonna require a little bit of voodoo… Simply put, the visible image is only a portion of the image sent to the screen. We’ll need to keep the same size sent image but redefine the visible, usable part. A good analog is fiddling with an older TV that has V. Size and V. Pos knobs on the back…

You’ll need to break out your shell and attack the xorg.conf modelines, specifically the height, width, and all the porch variables for your display. Instructions on how to do this are located here: Working with Modelines while a more in-depth explanation of the technology can be found here: Video Timings. I actually found reading the second one helped understand the how-to, but to each his own… Good luck!

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