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notro / fbtft

Linux Framebuffer drivers for small TFT LCD display modules. Development has moved to https://git.kernel.org/cgit/linux/kernel/git/gregkh/staging.git/tree/drivers/staging/fbtft?h=staging-testing
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Adafruit PiTFT Rasbian Output Squashed horizontally when using FBCP #144

Closed wow0w closed 10 years ago

wow0w commented 10 years ago

Hi, the FBTFT kernel works as intended when outputting directly to the display, but when mirroring fb0 to fb1 using fbcp the display appears horizontally squashed. For example, when I set the framebuffer size in config.txt to 320x240 (the native resolution of the tft) there are black bars on each side of the screen and the image is squashed, while a resolution of 400x240 fills the full screen, but is still squashed.

Doing some tests, any multiples of 480x320 (960x640, etc.) fully fill the tft with increasingly small text, but multiples of 320x240 (720x480, etc.) always have black bars on each side. Other random resolutions (720x320) have vertical black bars, which leads me to believe that fbcp is expecting the tft to have a resolution of 480x320 (or there abouts).

Therefore, I am wondering how to change this output to the 320x240 of the PiTFT so that the image is no longer squashed. Thanks in advance.

Edit: When the pi is rebooted without an hdmi display connected, even 480x320 no longer fills the screen, with both vertical and horizontal bars. 320x240 doesn't work properly, either. However, when running minecraft, the game floats out of its window and touches the left border of the screen.

wow0w commented 10 years ago

My bad. I've found that adjusting the overscan settings to -40 has solved the problem. I'm still unsure why it was the wrong resolution in the first place, but that doesn't really matter.