[Debian-eeepc-devel] External monitor

[Ben Armstrong]

On Tue, 20 May 2008 17:09:29 +0200
Robert Epprecht <epprecht at solnet.ch> wrote:
> The wiki has a similar suggestion:
> http://wiki.debian.org/DebianEeePC/HowTo/Configure
> It sets COMBINED_DISPLAY_SWITCHES="--above LVDS\ --auto" in
> /etc/default/eeepc-acpi-scripts
> 
> I would be interested to learn which way to tell people to use.
> (I don't know anything about X)

It's a hard decision to make, which is why we left it at a "lowest
common denominator" default of 640x480.  While this is not the best
looking, our line of reasoning is as follows:

1. If the LCD and VGA displays are separate, what will fit in the
maximum virtual size of 2048x2048?

We would have liked to say --right-of or --left-of, since that's a
common arrangement for an Eee and an external monitor, but let's take
the 800x480 Eee LCD display and an external display running at
1680x1050, for example.  1680+800 = 2480, which exceeds the 2048
maximum.  If you try to adjust the Virtual size to fit this, your X
server will crash constantly.  And while --above and --below should
work, not all window managers deal with this gracefully, often leaving
a panel drawn in the middle of the display, and/or sized too wide for
the LCD so that the left part is truncated.  So it seems there is no
good default choice here for separate displays.

2. If the displays aren't separate, do we turn off the LCD or share the
display between the LCD and VGA?

While I have heard that turning off the LCD is useful for some people,
I think sharing the display so that the LCD and VGA show the same thing
is less surprising.  So we opted for shared.

3. If the displays are shared, what is most likely to work with all
external monitors *and* the LCD?

While --auto would normally take care of this for you, we found that
this would pick a desktop size bigger than could fit on the LCD, so
that you would only see the upper left corner of the display.  This is
certainly a surprising result!  So we chose 640x480 as the "lowest
common denominator" that is supported both by the LCD and VGA.  Doesn't
look great, but is likely to work on most external monitors.  We leave
it as a doc point for the user to change themselves if they don't like
the default.

Ben