Raspberry Pi HDMI Overscan

I had a problem when I moved my Raspberry Pi over to using a 4K display, which is just about the only resolution that professional displays come in these days, as manufacturers have all moved on to 4K as a standard. The problem was with overscanning and the display not having the ability to correctly scale the image signal coming from the Raspberry Pi, which was still a 1920x1080 signal.

There's a collection of settings in config.txt on the Raspberry Pi that can mitigate this problem:

disable_overscan
overscan_left
overscan_right
overscan_top
overscan_bottom

For me, I deleted all the explicit overscan settings, and enabled the disable_overscan setting.

Here's my fixed up config.txt:

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enable_uart=1
disable_overscan=1
disable_splash=1
dtparam=i2c_arm=on
dtparam=spi=on
dtparam=audio=on
gpu_mem=32

More settings and info can be found here: https://www.opentechguides.com/how-to/article/raspberry-pi/28/raspi-display-setting.html