How to change HDMI output resolution

ODROID-C2 can support various resolution on HDMI output, you can select one of supported resolutions for your display (LCD monitor or TV).

Supported resolutions

We provide you a simple but useful application, ODROID Utility. This helps you to change the resolution by menu as below and you can select one of them for your display. Once you select one, click the button Apply and Reboot. Then your ODROID-C2 will restart with new resolution.

Display Auto Detection using EDID

This section introduce you to change the resolution by manual, this would be helpful if you are failure to change the resolution and not able to sett the face of ODROID-C2.

The fact what initiate the resolution is from U-boot and the environment key is hdmimode. Probably your U-boot would have the one like this by default.

target

odroidc#print hdmimode
hdmimode=720p60hz

This will be passed to Linux kernel by bootargs just before Linux kernel is started. Here is the default value of bootcmd which starts Linux kernel. As you see, hdmimode is passing as boot argument.

target

odroidc2# print bootcmd
bootcmd=cfgload; setenv bootargs root=/dev/mmcblk0p2 rw init=/init rootwait console=ttyS0,115200 hdmimode=${hdmimode}
hdmitx=${cecconfig} logo=osd1,loaded,${fb_addr},${hdmimode} androidboot.hardware=odroidc2 androidboot.serialno=${fbt_id#}
androidboot.selinux=disabled;showlogo ${hdmimode}; movi read dtb 0 0x1000000; movi read boot 0 0x20000000;
booti 0x20000000 - 0x1000000

There are three ways to change hdmimode to change the resolution, you can replace 1080p60hz with the other resolution you wish to change for your display. And only the way with adjusting hdmimode arg value in boot.ini is available for ODROID-C2 so far, the other ways are in progress.

Currently, 720p60hz mode is fixed on U-Boot stage after power-on and reset. But you can change hdmimode temporarily using 'showlogo' command.

target

showlogo 1080p60hz

You can boot with boot.ini without changing U-boot environment values permanently. If boot.ini is existed in FAT partition ODROID-C2 does boot with it first, unless boot with default setting stored in U-boot environment. The example related to display is as following.

setenv hdmimode "720p60hz"
 
# CEC Configuration
setenv cecconfig "cecf"
 
# HDMI/DVI Mode Configuration
# This will enforce the signal type of display
# "hdmi" - For HDMI interface
# "dvi" - For DVI interface
setenv vout_mode "hdmi"
 
setenv bootargs "${rootopt} ${consoleopt} hdmimode=${hdmimode} hdmitx=${cecconfig} vout=${vout_mode} overscan_top=${top} overscan_left=${left} overscan_bottom=${bottom} overscan_right=${right} logo=${logoopt} ${androidopt} ${selinuxopt}"
 
showlogo ${hdmimode}