Taken from Raspberry Pi 2 User Guide by Vilros
If you connect your Pi to a television using an HDMI cable, Raspbian automatically selects a screen size that it decides will be the best for your setup. However, this is not always the highest resolution.
The configuration setting that controls how Raspbian selects the screen size is in the file /boot/config.txt
and you can adjust this setting with a text editor:
-
On the Application Launcher, click LXTerminal.
-
Type the following command and then press Enter:
tvservice -d edid
-
Type the following command and then press Enter:
edidparser edid
-
Find the video mode that you want to use, and make note of the mode number and whether it says “DMT mode” or “CEA mode”.
-
Type the following command and press Enter:
sudo nano /boot/config.txt
-
Press the Down Arrow key until you find the lines that begin with
#hdmi_group=
#hdmi_mode=
-
Remove the
#
from the start of both of those lines. -
If the video mode is DMT, change the
hdmi_group
to2
:
hdmi_group=2
- If the video mode is CEA, change the
hdmi_group
to1
:
hdmi_group=1
- Type the mode number after
hdmi_mode=
, for example:
hdmi_mode=16
- Find the line that reads
disable_overscan=0
and change it to:
disable_overscan=1
-
Press Ctrl + X.
-
Press Y, and then press Enter.
-
Restart the Raspberry Pi.