[ale] A question for the X gurus out there.

[Geoffrey]

Michael B. Trausch wrote:
> On Mon, 2007-03-05 at 21:50 -0500, Randal Jarrett wrote:
> 
>> I'm running SuSe SLED10.  
>>
>> I have 2 video cards, NVidia GeForce 7900 GS PCI-e cards,
>> not in SLI mode.  Each to a separate lcd.
>>
>> Most everything appears to work ok but I cannot drag
>> an object from one display to another. 
>>
>> Is it possible??  What am I missng??
> 
> 
> I am pretty sure that you can use Xinerama across two (or more) video
> boards.  Xinerama is an extension which allows the dragging between two
> different screens, though on all of the implementations that I know of
> (including X.org's), OpenGL only works on one of the displays.  All
> other displays will display a black area where OpenGL applications are
> supposed to be.

Can't answer the question on OpenGL, but I do know that when properly 
configured, Xinerama will work across two separate video cards as well 
as a single card with multiple outputs.  I've done both.  I've not had 
the opportunity to do this with Nvidia cards, I've always used ATI 
cards.  I know that for the ATI cards, 3d acceleration is not supported 
when using xinerama.

> The multi-screen mode (the non-Xinerama mode) where you have two
> different desktops is actually quite beneficial to use.  It is different
> from the way the Windows world works, sure, but with the right software
> (I use GNOME, Evolution, and Epiphany which all play nice in this
> configuration) you can be quite productive with two different displays,
> and run OpenGL applications on both of them.  Very nice.  Sure, you lose
> the "extended" desktop, but I think that is a small price to pay.  Your
> primary display will be :0.0 and your secondary one will be :0.1, and so
> forth, in this configuration.  (Xinerama just makes a really big desktop
> on :0.0, and Ximerama-aware window managers will display panels on each,
> if you configure them to do so.)

I'm a bit confused by your description above. So are you saying you can 
switch to :0.1 and you have another desktop?  You can do this by simply 
running multiple X servers.

I currently have a single desktop spread across two monitors (19" flat 
and 22" crt, works out nicely as the real estate on a 19" flat is 
roughly equivalent to the 22" crt).  I can drag windows from one to the 
other and have windows span both.

>> Under that other OS (M$) I can drag across as long as the
>> windows are not full screen. (sorry about bringing that up).

No experience with this, and don't plan on wasting my time trying it. :)

>>
>> Any suggestions??
> 
> 
> I would work with the non-Xinerama mode for a little while and see what
> you think of it.  It feels a bit awkward at first if you have gotten
> used to using more than one monitor on a Windows system.  However, there
> are definitely advantages.

I think it sucks, but that's just me.

-- 
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
  - Benjamin Franklin