Multiple Displays on Laptop

[Alex Deucher]

On Fri, 31 Dec 2004 16:13:57 -0500, Jason Van Patten <jvp at lateapex.net> wrote:
> Hi folks -
> 
> I hope I'm sending this to the right mailing list.  If not, could someone
> kindly redirect me?

the xorg ML is your best bet.

> 
> I'm trying to configure X to run on my laptop (IBM Thinkpad, ATI Mobility
> T2) like so: When the laptop is connected to a monitor (ie, docked) I'd like
> the X server to run at resolution 2048x1536.  The laptop's LCD can only
> handle 1600x1200, so that's what it displays.  Like a 16x12 window into a
> 2048x1526 background.
> 
> When I undock the laptop, I can use xrandr to drop the resolution down to
> 16x12 so the LCD screen shows the entire desktop.
> 
> I've been partially successful in getting this to work.  I'll include the
> interesting bits of my xorg.conf at the end of the message.  The last hurdle
> to overcome is the requirement for a DDC-capable monitor to be attached when
> X starts.  If the laptop is connected to such a monitor, everything works
> beautifully.  It comes up in 2048x1536, and the LCD displays 16x12 of it.
> 
> However, if I bring the X server up when the laptop isn't docked, or is
> connected to a monitor that isn't DDC capable, I get a fixed 1600x1200
> display and that's it.  I can't change it up to 2048x1536 or 1920x1440.
> 
> Also, if I do bring X up with the DDC monitor attached, then de-dock the
> laptop, and THEN try to resize the server (xrandr) the LCD blanks out.  It
> seems I HAVE to have it connected to a DDC monitor to enable this feature,
> and to resize the screen.
> 
> Any ideas?
> 
> The bits from the config that'll matter most:
> Section "Monitor"
>          Identifier   "Monitor0"
>          VendorName   "Monitor Vendor"
>          ModelName    "LCD Panel 1600x1200"
>          DisplaySize  410        300
>          HorizSync    30.0 - 130.0
>          VertRefresh  50.0 - 160.0
>          Option      "dpms" "off"
> EndSection
> Section "Device"
>          Identifier  "Videocard0"
>          Driver      "radeon"
>          VendorName  "Videocard vendor"
>          BoardName   "ATI FireGL Mobility T2"
>          Option      "SubPixelOrder" "NONE"
>          Option      "MonitorLayout" "LVDS,CRT"
>          Option      "MergedFB" "TRUE"
>          Option      "MetaModes" "1600x1200-2048x1536 1600x1200-1920x1440
> 1600x1200-1600x1200"
> EndSection
> 
> Section "Screen"
>          Identifier "Screen0"
>          Device     "Videocard0"
>          Monitor    "Monitor0"
>          DefaultDepth     24
>          SubSection "Display"
>                  Viewport   0 0
>                  Depth     16
>                  Modes    "800x600" "640x480"
>          EndSubSection
>          SubSection "Display"
>                  Viewport   0 0

you can accomplish this by adding a virtual line to your screen section:

                    Virtual 2048 1536

>                  Depth     24
>                  Modes     "2048x1536" "1920x1440" "1600x1200" "1280x1024"
> "1024x768" "800x600" "640x480"
>          EndSubSection
> EndSection
> 
> -----------
> Essentially, I want to tell the X server: Ignore DDC and do what I tell you.
>   I know best.  ... is that even possible?
> 

see above.

Alex

> Thanks!
> 
> jas
> --
> Jason Van Patten