MergedFB/Xinerama/LUT with radeon driver

Frédéric frederic.mantegazza at
Mon Aug 14 15:54:10 PDT 2006


I'm trying to help the developper of the Argyllcms project to add support 
for Xinerama on ATI/NVidia cards. I personnaly use the free radeon driver 
comming with standard Xorg package, with a ATI M9 Mobility, in MergedFB 
mode. And there are some problems with dual screen detection with Argyll. 
As one other user of Argyll package has similar problems with its NVidia 
card using TwinView, I hope understanding how things work in the radeon 
driver will help.

So, let me explain what are the problems.

1) When used MergedFB mode, the radeon driver provides Xinerama 
informations. So, with 2 monitors connected, the XineramaIsActive() 
function returns True, and XineramaQueryScreens() returns 2 as second 
argument. There is no problem to acces to first screen informations using 
XF86VidModeGetMonitor(), but then, it fails on second. Here is the error :

X Error of failed request:  BadValue (integer parameter out of range for 
  Major opcode of failed request:  136 (XFree86-VidModeExtension)
  Minor opcode of failed request:  4 (XF86VidModeGetMonitor)
  Value in failed request:  0x4c
  Serial number of failed request:  12
  Current serial number in output stream:  12

I'm sure there is a way to do that, because KDE handles this mode correctly  
(some other apps, like gqview, also handle this correctly, but they light 
use KDE information rather than directly use Xinerama low level 

So, could someone help me (us)? I attached the piece of code from Argyll 

2) The second problem is about LUT. When using xcalib, the loaded LUT is 
common for both screens. Is there a way, when using MergedFB mode, to load 
a different LUT for each screen?


PS : there is a parameter in radeon driver which disables Xinerama 
informations; if turned on, then KDE is unabled to maximize a window on 
only one screen, and fullscreen mode expand on both screens two. So, this 
is not an issue.

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