Overscan was my problem too. The Raspberry has a nice feature to easily compensate for overscan. It’s the raspi-config command that’s not available on Le Potato.
This was fixed through much trial and error plus research. BTW, xrandr was already installed in the Raspbian image I downloaded from Libre Computer, and I didn’t have to apt install it. I’m curious why the command is not available on your distro.
The best solution for the overscan problem is to check your TV’s menu settings to see if overscan can be turned off. My HDMI TV doesn’t have that feature.
If that fails, use xrandr to shift and scale your image. You can enter these commands in your terminal, sudo not required. This assumes you’re using 1920x1080 (1080p).60Hz refresh.
# This command scales the display and shifts it down and right.
xrandr --output HDMI-1 --mode 0x46 --transform 0.97,0,-48,0,0.98,-24,0,0,1
# This command brings the right and bottom edges onto the screen.
xrandr --output HDMI-1 --transform 1,0,-48,0,1,-24,0,0,1
The second xrandr sometimes complains about a parameter bad match, but it works.
If this doesn’t fix it for your monitor, play with the decimal numbers for scaling (0.97 for horizontal, and 0.98 for vertical). In the above, left/right borders are 48, and right/bottom borders are 24.
To make this change permanent on login, add these lines at the end of your ~/.profile file.
One important note. At first this might not look like it’s working when you look at the LXPanel. The reason is because LXPanel doesn’t seem to be aware of the screen dimension changes caused by the --transform, and it will be off the screen. To fix that, use LXPanel advanced settings to adjust the size and location of the panel. For me, 95% left-aligned panel with 5 margin worked.
Hope this helps.