========= HDMI Force RGB Option =======
<WRAP center round important>
  * Ubuntu : The available version should be the one released after Jun 20, 2016.
  * Android : Android Marshmallow v1.2 (Dec 19, 2016) or higher version is available.
</WRAP>

===== Issue Brief =====

With some TV monitors, there is a bug in their HDMI implementation that sometimes trigger the selection of the wrong colorspace in a magenta/green display.\\

{{:en:c2_forcergb_1.png?600}} \\
http://forum.odroid.com/viewtopic.php?f=141&t=20697#p137351

It looks TV reports that is capable of YUV422 or YUV444 but it's not indeed.\\
To avoid this situation, you can use **forcergb** option to set COLORSPACE_SPACE_RGB444 forcibly.

Here are more investigations and discussions in ODROID Forum.
  * http://forum.odroid.com/viewtopic.php?f=144&t=21780&hilit=forcergb
  * http://forum.odroid.com/viewtopic.php?f=141&t=21737
  * http://forum.odroid.com/viewtopic.php?f=144&t=20415&p=145208#p145208

===== How to set boot.ini to activate forcergb =====
To activate it, add **hdmitx=forcergb** in bootargs.
<code>
setenv bootargs ${bootargs} hdmitx=forcergb
</code>

Here is the catch.\\
The env **hdmitx** has other parameters related to HDMI CEC control.\\
If you use CEC options, the env format can be **hdmitx=cecf,forcergb** or **hdmitx=cec0,forcergb**.\\

The ODROID Forum user, wrxtasy from LibreELEC already implemented a good guide for this case.\\

https://github.com/wrxtasy/LibreELEC.tv.7.0/blob/libreelec-7.1/projects/Odroid_C2/bootloader/boot.ini

<code>
# Enable | Disable HDMI CEC Control                 
setenv hdmi_cec  "0"            # Disabled                      
# setenv hdmi_cec  "1"          # Enabled                       
# setenv hdmi_cec  "2"          # Enabled but disable auto TV switching ON
                                                  
# Force HDMI to use RGB colorspace regardless of TV request
# setenv hdmi_forcergb "0"      # Disabled         
setenv hdmi_forcergb "1"        # Enabled          

if test "${hdmi_cec}" = "0"; then setenv hdmitx "hdmitx=cec0"; fi
if test "${hdmi_cec}" = "1"; then setenv hdmitx "hdmitx=cecf"; fi
if test "${hdmi_cec}" = "2"; then setenv hdmitx "hdmitx=cec7"; fi

if test "${hdmi_forcergb}" = "1"; then setenv hdmitx "${hdmitx},forcergb"; fi

setenv bootargs "${rootopt} ${consoleopt} hdmimode=${hdmimode} ${hdmitx} vout=${vout_mode} ............"
</code>