[Libdlo] ubuntu 10.04 / Lilliput UM-70 as secondary screen doesn't work

scar scar at drigon.com
Mon Mar 21 17:55:20 PDT 2011

Hash: SHA256

hello all,

i'm using ubuntu 10.04 and have a Lilliput UM-70 displaylink-based
monitor.  i've found a patchwork of guides explaining how to get it
running without much luck.  the best i can do is get it running as a
primary monitor.  the gdm login window and my main desktop will show up
on it.  the UM-70 is a tiny 7" screen so this config is unacceptable.  i
would like it to be a secondary screen next to my primary screen that i
can drag stuff to, for example.

i've read that i need to blacklist fbcon,bitblit,font,tileblit.
frankly, i don't know what this blacklisting is supposed to do; it
doesn't seem to make any difference either way.

also, i would rather not have to add "vga=normal nomodeset" to the grub
command line since it destroys the high resolution that i can use on the
console on my main display.  again, using this doesn't seem to make any

in fact, i've undone those changes and gotten the displaylink device to
work fine as a primary screen using xorg.conf settings (i also still
have the modification to /etc/gdm/Init/Default).  i guess this is
commonly referred to as an extended desktop, which i what i'm interested in.

below is my xorg.conf which will make both screens work fine and i can
drag the mouse between them etc.  however, it seems, since the
displaylink device is set as 'Screen 0', that is where the gdm login
window shows up and where my main desktop is.  i thought it would be easy to
fix that by just changing around the Screen definitions in the
ServerLayout section, to something like this:

Section "ServerLayout"
	Identifier	"Server Layout"
	Screen	0	"Default Screen" 0 0
	Screen  1	"DisplayLinkScreen" RightOf "Default Screen"
	Option		"Xinerama" "Off"

while this does set my main LCD back to the primary screen and things
work OK there, it seems to disable the use of the displaylink device; no
desktop shows up and i cannot move the mouse outside of my main LCD
screen ('Default Screen')


Section "ServerLayout"
	Identifier	"Server Layout"
	Screen	0	"DisplayLinkScreen" 0 0
	Screen  1	"Default Screen" RightOf "DisplayLinkScreen"
	Option		"Xinerama" "Off"

Section "Device"
	Identifier	"Configured Video Device"
	Driver		"intel"

Section "Monitor"
	Identifier	"Configured Monitor"

Section "Screen"
	Identifier	"Default Screen"
	Monitor		"Configured Monitor"
	Device		"Configured Video Device"

Section "Device"
	Identifier	"DisplayLinkDevice"
	driver		"displaylink"
	Option	"fbdev"	"/dev/fb1"

Section "Monitor"
	Identifier	"DisplayLinkMonitor"

Section "Screen"
	Identifier      "DisplayLinkScreen"
	Device          "DisplayLinkDevice"
	Monitor         "DisplayLinkMonitor"
	DefaultDepth    16
	SubSection "Display"
		Depth   16
		Modes   "800x480"



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