All the following options belong to the TV's Monitor section.

To light two TVs/HDTVs, add proper options to the TV-2's Monitor section.

Basic Configuration

You may start from the basic options defined by Xorg.

Option       "Enable"                   "boolean"
Option       "Disable"                 "boolean"
Option       "Ignore"                    "boolean"
Option       "PreferredMode"    "string"
Option       "Position"                 "integer integer"
Option       "Rotate"                    "string"
Option       "LeftOf" ("RightOf", "Below", "Above")          "string"
Option       "MinClock"               "integer"
Option       "MaxClock"              "integer"

The following three options are exclusive, you can use only one or none. If none is set, X takes "enable" by default.

Option      "Enable"               "boolean" 
Option      "Disable"              "boolean" 
Option      "Ignore"                 "boolean"

Option "Enable" "boolean"

It means to light the TV/HDTV when starting X.

Option "Disable" "boolean"

It means not to light the TV/HDTV when starting X, but you could light it by the command "$ xrandr  --auto".

Option "Ignore" "boolean"

X will not create the output for the TV/HDTV. You could not light it dynamically by any means.

Option "PreferredMode" "string"

This is a must option to light TV/HDTV. It set the display mode which would apply to TV/HDTV, say "1024x768". Note that if the display device is disabled, you may not add this option. Otherwise, that display device could be lighted when X starts up.

Option "Position" "integer integer"

Set the start posotion of the output. The integers represents the position by two coordinates (x,y). The default value is "0 0". This option takes effect when two display devices are enabled. It makes no difference if only one is enabled.

Option "Rotate" "string"

Rotate the output of the display device. The valid string could be left, right, normal, inverted, and the corresponding rotation degree is 270, 90, 0, 180 (CW). The default value is normal. To enable HW rotation, get more information from Chapter 6. Configuring Hardware rotation

Option "LeftOf"      "string"
Option "RightOf"    "string"
Option "Below"      "string"
Option "Above"      "string"

Enable the extend mode. If this option is not set when two display devices are enabled, the display mode would be clone mode. The string after the operator is one of the display device you intend to light. However, it's forbidden to use this option when only one display device is enabled.

Option "MinClock"    "integer"
Option "MaxClock"   "integer"

Put constrains to the display device, in order to filter out some mode. Unit: Hz.

TV/HDTV related options

Besides the options mentioned above, the VIA accelerated Linux graphics driver implemented other options to fulfill special requirements.

Option "Type" "string"

This option specifies in which way the TV/HDTV is connected to the board. Valid types are External, Internal. External means the TV/HDTV is connected via external transmitter, i.e. VT1625. The default type is Internal.

Option "DIPort" "string"

This option specifies which digital port is occupied by the TV/HDTV. Valid ports are DFP_HIGH, DFP_LOW, DFP_HIGHLOW, DVP0, DVP1. The default value is determined by the display device and the Type setting. Usually, if Type is set to External, the default value is DVP1.

Option "SerialPort" "hex number"

This option is used to set the port to sense the external transmitter/encoder. The valid values are 0x25, 0x26, 0x2C, 0x31, 0x3D. If this option is not set, the VIA driver will sense the ports following this sequence: 0x2c-> 0x31-> 0x25-> 0x3D-> 0x26.

Option "DDCPort" "hex number"

This option is used to set the port to obtain EDID. The valid values are 0x25, 0x26, 0x2C, 0x31, 0x3D. The value is usually the same as SerialPort's. Thus, this option can not be set in most cases.

Option "Standard" "string"

Specify the TV standard. Valid standards are "1080I", "720P", "576P", "480P", "PAL", "NTSC". If you do not set it or specify an invalid value, the default "NTSC" will be used.

Option "Signal" "string"

Specify the signal type. Valid types are "YCbCr", "RGB", "Composite", "S-Video", "Composite+S-Video", "Composite+S-Video+RGB", "Composite+S-Video+YCbCr". The default type is S-Video.

Option "Scan" "string"

Valid values are "Over", "Fit", "Normal". The default is "Normal". Over (represents overscan) is where the image is scanned beyond the boundaries of the screen. TV manufacturers do this to eliminate the possibility of black boarders and non-video information appearing on the screen. Typical overscan is 5 - 10% which is a bit too much for an arcade-monitor-like usage. Fit means that the scanned image fits the boundaries of the screen. Normal (represents underscan) is where the image is scanned under the boundaries of the screen.

Option "DedotCrawl" "boolean"

When TV standard is NTSC and signal type is composite, there is chance to get poor image quality. This option is to improve the image quality for this specific setting. The default value is "False".

Note that to avoid DI port conflicts, it's better to ignore the display devices which are not to be used.

You can get a complete sample in Appendix D. X Config Sample (Using the XRandR Extension).