[ltp] thinkpad with external monitor howto (2001FP)

[Alex Deucher]

On Sun, 13 Feb 2005 22:02:49 -0800, Shaw Vrana <shawv@comcast.net> wrote:
> On Sunday 13 February 2005 07:51 pm, Alex Deucher wrote:
> > On Sun, 13 Feb 2005 17:45:55 -0800, Shaw <shawv@comcast.net> wrote:
> > > On Sunday 13 February 2005 03:35 pm, Alex Deucher wrote:
> > > > On Sun, 13 Feb 2005 14:31:05 -0800, Shaw <shawv@comcast.net> wrote:
> > > > > On Sunday 13 February 2005 01:51 pm, Alex Deucher wrote:
> > > > > > mergedfb is what you want.  You need to set a metamode for the set
> > > > > > up you want, eg:
> > > > > > Option "metamodes" "1024x768-1600x1200"
> > > > > > Option "crt2position" "clone"
> > > >
> > > > add 1600x1200 to your screen section:
> > > > even though crtc1 won't use it, mergedfb uses these modes as it's mode
> > > > pool.  Also for flexability you may want to add some other modes to
> > > > your metamodes.  Then you can use  xrandr to switch between then.
> > >
> > > I added the 1600x1200 to the front of the Modes in the screen section,
> > > though I did have it there previously as the 2nd element. (see mode line
> > > from above) I'm still finding that mergeFB disables itself because it
> > > cannot figure out the modes and/or metamodes.
> >
> > you shoudl probably remove the second screen section from your
> > serverlayout:
> >
> > Section "ServerLayout"
> >  Identifier  "layout1"
> >  Screen   "Screen 1"
> >  Screen   "ExternalLCD"   <---  REMOVE THIS LINE
> >  InputDevice "Mouse1"  "CorePointer"
> >  InputDevice "Keyboard1" "CoreKeyboard"
> > EndSection
> >
> > > I'm not sure if the order of the metamodes matters (1024x768-1600x1200 as
> > > opposed to 1600x1200-1024x768), so I added the later without any success.
> > > I also tried setting my monitorlayout option to lvds, crt  but as that
> > > didn't help I removed it once again.
> >
> > The order does matter.  the first is the mode for crtc1 (LCD in this
> > case) and the second is for crtc2 (vga port).
> >
> > > How have I manged to screw up the modes so mergeFB doesn't understand
> > > them? Or is there another part of the configuration I'm missing?
> >
> > you might also try and set the hsync and vrefresh for crtc2:
> 
> Removing my second Screen from the ServerLayout did the trick.  Thanks for
> sticking with me through this!
> 
> I was surprised to learn the solution was to remove the Screen I had setup to
> represent the external monitor.  Perhaps that is the way to approach the dual
> head display..?  I guess here we're setting up different views of the
> framebuffer, as opposed to Screens.

Well, the second screen entry is for "regular" multi-head. Regular
multihead works by loading the driver twice once for each head, so you
also need two device sections.  With mergedfb one instance of the
driver handles both heads so it's all handled with one device section.

Alex

> 
> In any event, it's beautiful.  Excellent work on this, Alex.
> 
> Thanks!
> Shaw
> 
> I've attached the working version of my xorg.conf for those who might stumble
> across this exchange later.  I've kept the ExternalLCD Screen definition,
> though it is unused.
> 
> 
>