Video Issues

Setting in /boot/config.txt

hdmi_drive=2

seems to solve issues related to HDMI in some cases.

Can't change Resolution

If you have had to use

hdmi_safe=1

to make your pi display on your display, you will only be able to get 640x480 resolution. To fix this you need to use these settings to allow different resolutions.

hdmi_force_hotplug=1
hdmi_drive=2

and then set

hdmi_group=1
hdmi_mode=16

to force a resolution (those settings are for 1080p 60hz). More options can be found at: http://elinux.org/RPiconfig#Video_mode_options

An example of a forced 4:3 ratio at 1024x768

hdmi_drive=2
hdmi_force_hotplug=1 
hdmi_group=2 
hdmi_mode=16 

Show and set the current video mode

Note: This guide is only for operating systems that use tvservice to change the video mode, e.g. Raspbian, Xbian, and OSMC.

tvservice -swill show the current video mode. Example:

tvservice -s
state 0x12000a [HDMI DMT (51) RGB full 4:3], 1600x1200 @ 60.00Hz, progressive

The option -m will show the CEA (HDMI) and DMT (DVI) modes that are supported by the display device:

tvservice -m CEA
tvservice -m DMT

The preferred mode that is listed as (prefer) can be set by the -p option:

tvservice -p

Any other mode has to be specified by its Group (CEA or DMT) and the mode number that was listed by the -m option. Example for the mode 1600x1200 @ 60.00Hz in the example above:

tvservice -e "DMT 51"
Powering on HDMI with explicit settings (DMT mode 51)

Reset the frame buffer after changing the video mode

After changing the video mode via tvservice, it may necessary to reset the frame buffer. This can be achieved by changing its colour depth to 8 and then back to 16:

fbset -depth 8 && fbset -depth 16

Switch the display off and on again

The -o (off) option of tvservice disables the video output. It can be switched on again by either the -p (preferred) option or the -e (explicit) option, see above. Example:

tvservice -o
Powering off HDMI
tvservice -p
Powering on HDMI with preferred settings