xf86-video-ati, XRandR 1.2, and what used to be MergedFB

Marius Groeger mgroeger at sysgo.com
Fri Sep 14 07:17:04 PDT 2007

Hello List,

I'm running the following setup (duck and cover):
- IBM T43 with ATI x300
- Kubuntu Feisty
- xserver-xorg-core from 
  3v1n0.tuxfamily.org which is a 1.3 Xserver with some 1.3.99 fixes 
  backported for Feisty by from Trevino
- self-compiled xf86-video-ati off anongit
- self-compiled Mesa DRI off anongit
- self-compiled DRM kernel modules off anongit

Usually I'm on Feisty's standard xf86-video-ati 6.6.3 and are 
successfully running a MergedFB setup with a 1400x1050 on the LVDS and 
1280x1024 on an external VGA screen, which works quite ok. 

In my spare time however, hunting for a stable Google-Earth 3d / 
compiz, I'm trying to get some of the exciting new stuff to work, most 
importantly XRandR 1.2 and the supposedly much improved EXA code.

Strage thing 1)
Anyway, after booting KDE I see a funny thing: KDE seems to think 
there are two screens, but they're displayed both(!) on the LVDS. If I ask
to identify both screens, it looks like this:

   |         |             |
   |   [2]   |             |
   |         +             |
   +---------+ [1]         |
   |                       |
   |                       |
   |                       |

xrandr says:
  Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 2680 x 1050
  VGA-0 connected (normal left inverted right)
     1280x1024      60.0 +   59.9  
     1152x864       60.0  
     1024x768       60.0  
     800x600        60.3  
     640x480        60.0  
     720x400        70.1  
  DVI-0 disconnected (normal left inverted right)
  LVDS connected 1400x1050+0+0 (normal left inverted right) 0mm x 0mm
     1400x1050      60.2*+
     1280x800       60.0  
     1280x768       60.0  
     1024x768       60.0  
     800x600        60.3  
     640x480        59.9  
  S-video disconnected 800x600+0+0 (normal left inverted right) 0mm x 0mm
    800x600 (0x5b)   38.2MHz
          h: width   800 start  832 end  912 total 1024 skew    0 clock   37.4KHz
          v: height  600 start  603 end  607 total  624           clock   59.9Hz

So, the LVDS and VGA-0 are detected ok, but the VGA-0 is dark and I 
get two sort-of embedded screens.

Strage thing 2)
First thing I need to do to anything reasonable is to turn off 
S-video (xrandr --output S-video --off) as was discussed in another 
thread. Only then I can begin to operate on VGA-0.

Strage thing 3)
xrandr --fb 2680x1050 --output VGA-0 --right-of LVDS seems to do it for me
almost entirely: I get what was my MergedFB setup, KDE kicker refreshes, the
weird embedded screen disappears, but: VGA-0 remains pitch-dark! It looks
like just one tiny DISPLAY_ENBALE bit is missing. 

I'm able and willing to do some debugging and testing here, but I need some
pointers into the xf86-video-ati source first; I'm pretty lost. 


Marius Groeger
SYSGO AG                      Embedded and Real-Time Software
Voice: +49 6136 9948 0                  FAX: +49 6136 9948 10
www.sysgo.com | www.elinos.com | www.osek.de | www.pikeos.com

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