X-Server (Linux)
Introduction
The X-Server allows graphical user interfaces on a Linux system. Typically a desktop environment like Gnome, KDE, or LXDE runs on top of this X-Server which allows starting other programs. If such a program is an X enabled graphical application it will connect to the X-Server directly to draw itself on the screen. Our default images ship with LXDE (a lightweight desktop environment, see the LXDE Page).
There is a related article that covers the topic of Display Output, Resolution and Timings.
From our BSP 5 onward, Wayland/Weston is being used by default. XWayland provides a compatibility layer for X-based applications. You can learn more about it on the following resources:
Configuration
Nowadays the X-Server comes with reasonable auto-configuration functions. Nevertheless, we ship our modules with a default configuration file (located under /etc/X11/xorg.conf). The xorg.conf mainly chooses which Device Dependent X (DDX) driver to load. Our default configuration files select the following driver:
| Module SoC | DDX driver |
|---|---|
| i.MX 6 | vivante |
| i.MX 7 | fbdev |
| Tegra 2 and 3 | tegra (binary only) |
| Vybrid | fbdev (Linux <= 4.1) |
| Vybrid | modesetting (Linux >= 4.4) |
Otherwise, the default configuration does not alter a lot but uncommented examples show how to override automatically configured options.
If X-Server configuration is needed using the command line utility xrandr is the easiest way to do this. However, this configuration is not persistent. Either one should add those commands to the LXDE auto-start settings (/etc/xdg/lxsession/LXDE/autostart) or try to create a static configuration using xorg.conf.
Colibri/Apalis i.MX6
Interface Mode (Resolution)
i.MX6 based modules support EDID on DVI-D (aka HDMI) and makes use of it allowing the user to configure resolutions supported by the monitor.
Changing resolution through XRandR
The supported resolutions and required timings are fetched through EDID, see below the xrandr command output:
root@apalis-imx6:~# xrandr
Screen 0: minimum 240 x 240, current 1920 x 1080, maximum 8192 x 8192
DISP3 BG connected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
S:1920x1080p-60 60.00*+
S:1920x1080p-50 50.00
S:1920x1080p-30 30.00
S:1920x1080p-25 25.00
S:1920x1080p-24 24.00
S:1280x720p-60 60.00
S:1280x720p-50 50.00
S:720x576p-50 50.00
S:720x480p-60 59.94
V:640x480p-60 60.00
Set one of the available resolutions:
Colibri i.MX6:
root@colibri-imx6:~# xrandr --output DISP3\ BG\ -\ DI1 --mode U:1280x720p-120
[ 39.880412] mxc_sdc_fb fb@0: 1280x720 h_sync,r,l: 40,110,220 v_sync,l,u: 5,5,20 pixclock=148500000 Hz
Apalis i.MX6:
root@apalis-imx6:~# xrandr --output DISP3\ BG --mode S:1920x1080p-60
[ 566.499079] mxc_sdc_fb fb@0: 1920x1080 h_sync,r,l: 44,88,148 v_sync,l,u: 5,4,36 pixclock=148500000 Hz
The character "\" must be used since the output name has spaces.
Changing resolution through xorg.conf
An available resolution can be configured as "preferable" in the "/etc/X11/xorg.conf" as well:
Section "Monitor"
Identifier "DISP3 BG"
Option "PreferredMode" "S:1280x720p-60"
EndSection
If the connected monitor does not provide the preferred resolution, the X-Server will automatically choose the next closest resolution.
Adding new resolutions
There is a possibility that your monitors' correct resolution may not be detected. If this happens, you can create a new resolution mode.
The cvt utility is used to get a correct modeline for XRandR, the correct syntax is cvt width height refreshrate, see below:
root@colibri-imx6:~# cvt 1920 1080 30
# 1920x1080 29.95 Hz (CVT) hsync: 33.01 kHz; pclk: 79.75 MHz
Modeline "1920x1080_30.00" 79.75 1920 1976 2168 2416 1080 1083 1088 1102 -hsync +vsync
Create a new mode using the above modeline:
xrandr --newmode "1920x1080_30.00" 79.75 1920 1976 2168 2416 1080 1083 1088 1102 -hsync +vsync
Add the mode to the current display output:
xrandr --addmode DISP3\ BG 1920x1080_30.00
Set the new resolution:
xrandr --output DISP3\ BG --mode 1920x1080_30.00
The changes are lost after reboot, to set up the resolution persistently, create the file ~/.xprofile with the content:
#!/bin/sh
xrandr --newmode "1920x1080_30.00" 79.75 1920 1976 2168 2416 1080 1083 1088 1102 -hsync +vsync
xrandr --addmode DISP3\ BG\ -\ DI1 1920x1080_30.00
LVDS or RGB
It is not possible to change resolution timings from X-Server directly. However, the mode is inherited from the framebuffer device (mxcfb). Refer to the Display Output, Resolution and Timings (Linux) documentation to change default settings.
Colibri i.MX6ULL and Colibri i.MX7
It is not possible to change resolution timings from X-Server directly, however, the mode is inherited from the framebuffer device (mxsfb). Refer to the Display Output, Resolution and Timings (Linux) documentation to change default settings.
Tegra 2 and 3 based Modules
General Notes on xorg.conf
The Tegra driver uses XRandR extensions and those do not support the old style (Xinerama) multi head configuration. Instead, only one Screen section has to be active and the Monitors are linked by using Option "Monitor-$connector" "$monitor-section" in the Device section. Refer to our sample configuration on the module or http://www.thinkwiki.org/wiki/Xorg_RandR_1.2 for more information.
Interface Mode (Resolution)
On some connectors the hardware supports EDID. Our BSP makes use of that and allows the user to configure resolutions supported by the monitor.
| Description | Output 1 | Output 2 |
|---|---|---|
| Framebuffer boot name | tegrafb0 | tegrafb1 |
| Framebuffer device | /dev/fb0 | /dev/fb1 |
| X-Server name | LVDS-1 | HDMI-1 |
| Connector on Evalboard | LVDS/RGB/VGA | DVI-D |
| Connector on Iris | DVI-A | DVI-D |
| Supports EDID (Software) | No | Yes |
On DVI-D (HDMI-1 in X-Server terms) using XrandR
The supported resolutions and required timings are fetched through EDID on this output. One can check the currently used resolution and list the available resolutions:
root@colibri:~# xrandr
Screen 0: minimum 256 x 128, current 640 x 480, maximum 2048 x 2048
LVDS-1 connected 640x480+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
640x480 0.0*+
HDMI-1 connected 640x480+0+0 (normal left inverted right x axis y axis) 510mm x 287mm
1920x1080 60.0 + 50.0
1680x1050 59.9
1280x1024 75.0 60.0
1440x900 59.9
1280x960 60.0
1280x800 59.9
1152x864 75.0
1280x720 60.0 50.0
1024x768 75.0 70.1 60.0
832x624 74.6
800x600 72.2 75.0 60.3 56.2
720x576 50.0
720x480 59.9
640x480 75.0 72.8 66.7 59.9*
720x400 70.1
Set one of the available resolutions:
root@colibri:~# xrandr --output HDMI-1 --mode 1920x1080
[ 237.924744] tegradc tegradc.1: Using mode 1920x1080 pclk=148500000 href=1 vref=1
Display modes are solely negotiated through DDC/EDID, "xrandr --newmode" does not work.
On DVI-D (HDMI-1 in X-Server terms) using xorg.conf
An available resolution can be configured as "preferable" in the xorg.conf as well:
Section "Monitor"
Identifier "HDMI-1"
Option "PreferredMode" "720x400"
...
EndSection
If the connected monitor does not provide the preferred resolution, the X-Server will automatically choose the next closest resolution.
There exists some NVIDIA proprietary dependency on the primary LVDS resolution having to be equal or higher than the secondary HDMI one. Alternatively one can directly put a manual xrandr configuration of the form 'xrandr --output HDMI-1 --mode 1280x720' into a graphical auto start file as explained here.
On LVDS, RGB or VGA (LVDS-1 in X-Server terms)
It is not possible to change resolution timings from X-Server directly. However, the mode is inherited from the framebuffer device (fbdev). Refer to the Display Output, Resolution and Timings (Linux) documentation to change default settings.
Dual Screen Layout
XRandR
Please note that the vertical and horizontal resolution is limited to 2048 pixels by hardware:
root@colibri_t20:~# xrandr --output HDMI-1 --mode 1920x1080
root@colibri_t20:~# xrandr --output LVDS-1 --mode 1920x1080
root@colibri_t20:~# xrandr --output LVDS-1 --right-of HDMI-1
xrandr: screen cannot be larger than 2048x2048 (desired size 3840x1080)
xorg.conf
The xorg.conf configuration files allow to configure the Dual Screen Layout using the Monitor section as well. This sample shows a clone with an X-Axis offset of 80 pixels:
Section "Monitor"
Identifier "HDMI-1"
...
Option "AboveOf" "LVDS-1"
Option "Position" "80 0"
EndSection
The keywords RightOf/LeftOf can be used as well, however LXDE seems to override those settings on start up. We therefore recommend to use the xrandr command and add that to the LXDE Session auto start entries.
Section "Monitor"
Identifier "HDMI-1"
...
Option "RightOf" "LVDS-1"
EndSection
Turning an output completely off can be archived by using the Option "Ignore":
Section "Monitor"
Identifier "HDMI-1"
Option "Ignore" "true"
...
EndSection
Colour Depth
By default, our X-Server configuration uses 16-Bit colour depth to save memory bandwidth (since the CPU and GPU share the memory, this leads to more bandwidth for the CPU). Lots of TFT displays can only show 18-Bit colours anyway.
In order to enable 24-Bit colour depth, use the "DefaultDepth" option in the screen section:
Section "Screen"
...
DefaultDepth 16
EndSection
Rotation
XRandR
root@colibri:~# xrandr --output HDMI-1 --mode 1680x1050 --rotation inverted
[ 493.075971] tegradc tegradc.1: switching framebuffer to 1680x1050
[ 493.076002] tegradc tegradc.1: using mode 1680x1050 pclk=119005000 href=1 vref=1
root@colibri:~# xrandr --output LVDS-1 --rotate inverted
xorg.conf
Extend the monitor section with the Rotate option:
Section "Monitor"
...
Option "Rotate" "inverted"
Possible options are: normal, left, right and inverted.
Due to a limitation of the Tegra binary driver, this is only possible for the HDMI-1 output. However, the LVDS-1 output supports rotation through xrandr (see above). We recommend to use the xdg auto start method to call xrandr immediately on LXDE session initialisation.
Mouse Coordinates
Under certain circumstances the mouse coordinates might get swapped. When using the touchscreen calibration, this will be inverted automatically. However, one can swap this using X-Input:
root@colibri_t20:~# export DISPLAY=:0.0
root@colibri_t20:~# xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ wm97xx touchscreen id=6 [slave pointer (2)]
⎜ ↳ MosArt Optical Mouse id=8 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ SCISSORS Keyboard id=7 [slave keyboard (3)]
List the X-Input properties:
root@colibri_t20:~# xinput list-props 8
Device 'MosArt Optical Mouse':
Device Enabled (115): 1
Coordinate Transformation Matrix (116): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
Device Accel Profile (236): 0
Device Accel Constant Deceleration (237): 1.000000
Device Accel Adaptive Deceleration (238): 1.000000
Device Accel Velocity Scaling (239): 10.000000
Evdev Axis Inversion (72): 0, 0
Evdev Axes Swap (71): 1
Axis Labels (241): "Rel X" (125), "Rel Y" (126)
Button Labels (242): "Button Left" (118), "Button Middle" (119), "But
ton Right" (120), "Button Wheel Up" (121), "Button Wheel Down" (122), "Button Horiz Wheel Left" (123), "Button Horiz Wheel Right" (124)
Evdev Middle Button Emulation (243): 0
Evdev Middle Button Timeout (244): 50
Evdev Wheel Emulation (245): 0
Evdev Wheel Emulation Axes (246): 0, 0, 4, 5
Evdev Wheel Emulation Inertia (247): 10
Evdev Wheel Emulation Timeout (248): 200
Evdev Wheel Emulation Button (249): 4
Evdev Drag Lock Buttons (250): 0
Configure a property accordingly:
root@colibri_t20:~# xinput set-prop 8 "Evdev Axes Swap" 0
To have this set automatically upon boot proceed as follows:
System - Preferences - Startup Applications
Add
Name: Mouse Coordinate Fix
Command: xinput set-prop 8 "Evdev Axes Swap" 0
Add
Close
Reboot
Keyboard Map
The X keyboard map can manually be set as follows (where ch is the layout and de the variant):
root@apalis-t30:~# setxkbmap ch de
To apply this setting over re-boots one can append the following to /etc/X11/xorg.conf:
Section "InputClass"
Identifier "Keyboard0"
MatchIsKeyboard "on"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "ch"
Option "XkbVariant" "de"
EndSection
Plus one has to remove the /etc/X11/Xinit.d/12keymap file as it otherwise interferes.
Tegra K1 based modules
Interface Mode (Resolution)
Apalis TK1 supports EDID on DVI-D (aka HDMI) and makes use of it allowing the user to configure resolutions supported by the monitor.
Changing resolution through XRandR
The supported resolutions and required timings are fetched through EDID, see below the xrandr command output:
root@apalis-tk1:~# xrandr
Screen 0: minimum 8 x 8, current 2560 x 1080, maximum 16384 x 16384
LVDS-0 connected 640x480+1920+0 (normal left inverted right x axis y axis) 0mm x 0mm
640x480 60.99*+
HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1920x1080 60.00*+ 50.00 30.63 30.03 25.52
1680x1050 60.00
1600x900 59.99
1440x900 59.98
1400x1050 59.99
1280x1024 75.03 60.02
1280x800 60.03
1280x720 60.00 59.67 50.00
1152x864 75.00
1024x768 60.01
800x600 75.00
720x400 70.04
640x480 75.00 61.05 60.00
Set one of the available resolutions:
root@apalis-tk1:~# xrandr --output HDMI-0 --mode 1920x1080
[ 2171.783136] tegradc tegradc.1: using mode 1920x1080 pclk=148500000 href=1 vref=1
Vybrid based modules
The Vybrid's display controller (DCU, Display Control Unit) supports only one output. Depending on the BSP version the Linux kernel and X-Server use a different driver for the display controller:
- BSP Version 2.5 and earlier (BSP with Linux kernel 4.1 and older): fbdev kernel driver, fbdev DDX driver
- BSP Version 2.6 and later (BSP with Linux kernel 4.4 and newer): DRM kernel driver, modesetting DDX driver
LXDM
The lightweight desktop manager can temporarily be stopped as follows:
systemctl stop lxdm
Or permanently be disabled as follows:
systemctl disable lxdm.service
systemctl disable xinput-calibrator.service
BSP V1.x
Display Manager (BSP V1.x)
By default the display manager (/usr/lib/libnvodm_disp.so) now only supports 640x480 @ 60 Hz on the TFT/LCD aka VGA interface. To change it back to support all modes proceed as follows:
root@colibri_t20:~# ln -fs /usr/lib/libnvodm_disp.so.allmodes /usr/lib/libnvodm_disp.so
And reboot.
Dual Screen Setup (BSP V1.x)
Unfortunately due to some interoperability issue with the GNOME monitor preferences application (e.g. System - Preferences - Monitors) and NVIDIA's Tegra 2 X driver the only way to get a dual screen setup to work reliably is by manual configuration.
Deactivate regular gnome display manager
Just add an exit 0 towards the top of /etc/init.d/gdm as follows:
root@colibri_t20:~# vi /etc/init.d/gdm
#! /bin/sh
exit 0
...
Manually start NVIDIA Daemon and X Server
Now after rebooting the NVIDIA daemon and X server have to be manually started as follows:
root@colibri_t20:~# nvrm_daemon --daemon&
[ 135.698108] tegra-i2c tegra-i2c.0: no acknowledge
root@colibri_t20:~# X -ac -dumbSched -nolisten inet6&
X.Org X Server 1.9.4
Release Date: 2011-02-04
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.37-00004-g3462985 x86_64
Current Operating System: Linux colibri_t20 2.6.36.2-g590b97a-dirty #5 SMP PREEMPT Sat Sep 24 01:48:04 CEST 2011 armv7l
Kernel command line: mem=384M@0M nvmem=128M@192M vmalloc=248M video=tegrafb envsector=2d00 nvsku=000-00000-0000-000 root=/dev/mtdblock0 ip=off rw rootfstype=yaffs2 mtdparts=tegra_nand:1018368K@28160K(userspace) console=ttyS0,115200n8
Build Date: 08 May 2011 05:38:34PM
Current version of pixman: 0.22.0
Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Feb 24 16:49:22 2014
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
NvRmModuleResetWithHold deassert MOD[32] INST[0]
root@colibri_t20:~# export DISPLAY=:0.0
Configure Dual Screen Layout
Please note that the total resolution is currently limited by 2 K:
root@colibri_t20:~# xrandr --output HDMI --mode 1920x1080
root@colibri_t20:~# xrandr --output TFTLCD --mode 1920x1080
root@colibri_t20:~# xrandr --output TFTLCD --right-of HDMI
xrandr: screen cannot be larger than 2048x2048 (desired size 3840x1080)
576p Side by Side
root@colibri_t20:~# xrandr --output HDMI --mode 720x576
root@colibri_t20:~# xrandr --output TFTLCD --mode 720x576
root@colibri_t20:~# xrandr --output TFTLCD --right-of HDMI
Application Positioning
As there is currently no window manager active, applications can manually be positioned as explained here.
Firefox
Unfortunately Firefox does not accept generic geometry parameters but accepts width and height:
root@colibri_t20:~# firefox -height 576 -width 720&
Xterm on the lower VGA Screen
root@colibri_t20:~# opkg install xterm
Installing xterm (266-r5.0.9) to root...
Downloading http://www.angstrom-distribution.org/feeds/next/ipk/eglibc/armv7a-vfp/base/xterm_266-r5.0.9_armv7a-vfp.ipk.
Configuring xterm.
root@colibri_t20:~# xterm -geometry 720x576+720+0&
EDID BSP V1.x
NVIDIA's display manager /usr/lib/libnvodm_disp.so can be setup to do software EDID. Software EDID will always take precedence if present. Customers requiring custom display timings can now proceed as follows to load their custom software EDID:
./EDIDUpdate.pl --load --EDID=output.edid --display=lvds --module=./libnvodm_disp.so
If you do not have a binary EDID handy our latest Linux packages also contain an EDID generator tool:
./generate_edid
As follows an explanation of the required timing values:
Pixel Clk (in 10KHz)
H Active
H Blank (Horizontal sync width plus back porch plus front porch)
V Active
V Blank (Vertical sync width plus back porch plus front porch)
H Offset (Horizontal front porch)
H Pulse (Horizontal sync width)
V Offset (Vertical front porch)
V Pulse (Vertical sync width)
Example for 1024x768@70Hz timings for a CRT Monitor
Pixel Clk 7500 (7500 * 10kHz)
H Active 1024 (Pixel)
H Blank 304 (Pixel)
V Active 768 (Lines)
V Blank 38 (Lines)
H Offset 24 (Pixel)
H Pulse 136 (Pixel)
V Offset 3 (Lines)
V Pulse 6 (Lines)
The tools 'EDIDUpdate.pl' and 'generate_edid' can be found in the T20 Image tarball download. They are executed on your Linux host. The best practice is to mark the software EDID library with an explanatory ending and create a symbolic link to the one to be used. e.g.
/usr/lib/libnvodm_disp.so -> libnvodm_disp.so.fullhdonly
/usr/lib/libnvodm_disp.so.fullhdonly
Remote X
To allow for remote X clients to connect to the X server running on the Colibri T20 one has to adjust either /etc/gdm/gdm.conf or /etc/gdm/custom.conf as follows:
[security]
DisallowTCP=false
After restarting GDM or rebooting one further has to explicitly disable access control as follows:
root@colibri_t20:~# export DISPLAY=:0
root@colibri_t20:~# xhost +
access control disabled, clients can connect from any host
Now any X client can connect (note 192.168.10.2 is my module's IP address):
sumo@sumo-PORTEGE-R700:~$ export DISPLAY=192.168.10.2:0
sumo@sumo-PORTEGE-R700:~$ xclock
Warning: Missing charsets in String to FontSet conversion
Warning: Unable to load any usable fontset
^C
sumo@sumo-PORTEGE-R700:~$ xdpyinfo
name of display: 192.168.10.2:0.0
version number: 11.0
vendor string: The X.Org Foundation
vendor release number: 10904000
X.Org version: 1.9.4
maximum request size: 16777212 bytes
motion buffer size: 256
bitmap unit, bit order, padding: 32, LSBFirst, 32
image byte order: LSBFirst
number of supported pixmap formats: 7
supported pixmap formats:
depth 1, bits_per_pixel 1, scanline_pad 32
depth 4, bits_per_pixel 8, scanline_pad 32
depth 8, bits_per_pixel 8, scanline_pad 32
depth 15, bits_per_pixel 16, scanline_pad 32
depth 16, bits_per_pixel 16, scanline_pad 32
depth 24, bits_per_pixel 32, scanline_pad 32
depth 32, bits_per_pixel 32, scanline_pad 32
keycode range: minimum 8, maximum 255
focus: window 0x120001f, revert to Parent
number of extensions: 23
BIG-REQUESTS
Composite
DAMAGE
DOUBLE-BUFFER
DPMS
Generic Event Extension
MIT-SCREEN-SAVER
MIT-SHM
RANDR
RECORD
RENDER
SHAPE
SYNC
TEGRA-EGL
X-Resource
XC-MISC
XFIXES
XFree86-VidModeExtension
XInputExtension
XKEYBOARD
XTEST
XVideo
XVideo-MotionCompensation
default screen number: 0
number of screens: 1
screen #0:
dimensions: 1920x1080 pixels (508x285 millimeters)
resolution: 96x96 dots per inch
depths (7): 24, 1, 4, 8, 15, 16, 32
root window id: 0x5f
depth of root window: 24 planes
number of colormaps: minimum 1, maximum 1
default colormap: 0x20
default number of colormap cells: 256
preallocated pixels: black 0, white 16777215
options: backing-store NO, save-unders NO
largest cursor: 64x64
current input event mask: 0xfa8033
KeyPressMask KeyReleaseMask EnterWindowMask
LeaveWindowMask ExposureMask StructureNotifyMask
SubstructureNotifyMask SubstructureRedirectMask FocusChangeMask
PropertyChangeMask ColormapChangeMask
number of visuals: 2
default visual id: 0x21
visual:
visual id: 0x21
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x5d
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
xorg.conf
As follows an example configuration file for an 800 by 480 touch TFT panel:
root@colibri_t20:~# cat /etc/X11/xorg.conf.tfttouch
# This is the minimal configuration necessary to use the Tegra driver.
# Please refer to the xorg.conf man page for more configuration
# options provided by the X server, including display-related options
# provided by RandR 1.2 and higher.
# Disable extensions not useful on Tegra.
Section "Module"
Disable "dri"
Disable "dri2"
Disable "glx"
SubSection "extmod"
Option "omit xfree86-dga"
EndSubSection
EndSection
Section "Device"
Identifier "Tegra"
Driver "tegra"
# VirtualDesktop indicates which virtual desktops should be used by X.
# X will use the specified virtual desktop *and* the next one. In
# order for an external app to share a display with the X server, it
# needs to use the same virtual desktop. Valid values are integers 0
# (default) or 1.
# Option "VirtualDesktop" "1"
# OverlayDepth is a 32-bit integer which is used to control overlay
# stacking order. The overlay with the lowest depth is in front of
# all others. This value has meaning only when multiple overlays are
# present on a display.
# Option "OverlayDepth" "255"
# OverlayCombineMode determines how the X overlay is combined with the
# overlay behind it during scanout. Available modes are: Opaque
# (default), SourceAlphaBlend, and PremultSourceAlphaBlend. This
# value has meaning only when an external process has created a
# display which is behind the X server.
# Option "OverlayCombineMode" "PremultSourceAlphaBlend"
# ARGBHWCursor controls whether the X driver uses an overlay to
# display 32-bit "true-color" cursors, or whether such cursors are
# emulated in software. Valid values are "true" (default) to enable
# hardware cursors, and "false" to disable them.
Option "ARGBHWCursor" "false"
EndSection
Section "ServerFlags"
# Set the basic blanking screen saver timeout in minutes. 0 to disable.
Option "blank time" "0"
# Set the DPMS timeouts. These are set here because they are global
# rather than screen-specific. These settings alone don't enable DPMS.
# It is enabled per-screen (or per-monitor), and even then only when
# the driver supports it.
Option "standby time" "0"
Option "suspend time" "0"
Option "off time" "0"
EndSection
Section "Monitor"
Identifier "TFTLCD"
EndSection
Section "Screen"
Identifier "Screen TFTLCD"
Device "Tegra"
Monitor "TFTLCD"
DefaultDepth 16
SubSection "Display"
Depth 16
Modes "800x480"
ViewPort 0 0
Virtual 800 480
EndSubsection
EndSection
Section "ServerLayout"
Identifier "TouchView"
Screen "Screen TFTLCD"
EndSection
To use this configuration just rename /etc/X11/xorg.conf.tfttouch to /etc/X11/xorg.conf and reboot.
Depth can be either 16 or 24 but the later requires a kernel change. See Display Output, Resolution and Timings (Linux) and adjust the colour depth (bits_per_pixel to 32) in the *[hdmi]_fb_data struct accordingly.
Xrandr
root@colibri_t20:~# export DISPLAY=:0
root@colibri_t20:~# xrandr
Screen 0: minimum 256 x 128, current 1920 x 1080, maximum 2048 x 2048
TFTLCD connected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1920x1200 64.9
1920x1080 72.1*
1600x1200 77.9
1680x1050 84.8
1400x1050 101.7
1280x1024 114.0
1440x900 115.3
1280x960 121.6
1366x768 142.4
1360x768 143.0
1152x864 150.1
1280x768 152.0
1280x720 162.1
1024x768 189.9
1024x600 242.9
800x600 310.7
720x576 359.4
848x480 366.1
800x480 388.0
720x480 431.0
640x480 484.7
480x272 1135.8
320x240 1925.0
CRT disconnected (normal left inverted right x axis y axis)
HDMI connected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0m
m
1920x1080 72.1*+
1280x720 162.1
720x576 359.4
720x480 431.0
root@colibri_t20:~# xrandr --output TFTLCD --mode 1280x720
root@colibri_t20:~# xrandr --output HDMI --mode 1280x720
NvRmModuleResetWithHold deassert MOD[32] INST[0]
root@colibri_t20:~# xrandr
Screen 0: minimum 256 x 128, current 1280 x 720, maximum 2048 x 2048
TFTLCD connected 1280x720+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1920x1200 64.9
1920x1080 72.1
1600x1200 77.9
1680x1050 84.8
1400x1050 101.7
1280x1024 114.0
1440x900 115.3
1280x960 121.6
1366x768 142.4
1360x768 143.0
1152x864 150.1
1280x768 152.0
1280x720 162.1*
1024x768 189.9
1024x600 242.9
800x600 310.7
720x576 359.4
848x480 366.1
800x480 388.0
720x480 431.0
640x480 484.7
480x272 1135.8
320x240 1925.0
CRT disconnected (normal left inverted right x axis y axis)
HDMI connected 1280x720+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1920x1080 72.1 +
1280x720 162.1*
720x576 359.4
720x480 431.0
DVI-D resp. HDMI display modes are solely negotiated through DDC/EDID while the parallel RGB resp. LVDS display mode has to be defined within the kernel, "xrandr --newmode" does not work.