RandR extension missing error

[Hal V. Engel]

On Sunday 03 June 2007 17:27, Andy Ritger wrote:
> Hi Hal, below:
>
> On Sun, 3 Jun 2007, Hal V. Engel wrote:
snip
> > nvidia-settings has a number of problems.  The main one of concern here
> > is that when I tried to change the screen resolution it complained about
> > randr not being available.  It appears that it does not have this
> > functionality independent of randr.
>
> Right, nvidia-settings uses the NV-CONTROL X extension to configure
> MetaModes, and then uses RandR (1.1) to switch between the MetaModes.
>
> If you're interested, you can find out more about that in the "Dynamic
> TwinView" section of this page:
>
>     
> http://us.download.nvidia.com/XFree86/Linux-x86/1.0-9755/README/appendix-g.
>html
>
> But, yes, there seems to be something more fundamentally wrong with your
> installation since no RandR extension is available at all.
>
> From your earlier post, I see that you're using two X screens.  Are you
> also using the Xinerama extension?  RandR gets disabled in the core X
> server when Xinerama is enabled.

I have Xinerama enabled.  I turned it off and tried to use xrandr to get 
things to work in a reasonable way (IE. the ability to move application 
windows between displays and the ability to have windows span multipule 
displays) and was not able to get anything to work.  Perhaps this is the case 
because of being limited to randr 1.1 functionality by the video driver?   In 
addition, my user startup scripts set the dislpay gamma tables for each 
monitor and it appears that the second display does not have it's gamma table 
set at startup.  So with the current nvidia drivers randr is not very usefull 
even if it allows me to resize the display.   But it might help at least a 
little with the applicaiton testing issue. 

So how do I get Xinerama features with out Xinerama enabled?  Twinview is not 
the correct answer since twinview does not allow for correctly setting the 
video card gamma tables for the displays.  IE. in twinview the XFree86 
VidMode extension does not work correctly for multipule displays (I have been 
told that it also does not work correctly for drivers that use mergefb).  
Only one gamma table is available for both displays and this is all but 
useless for my needs.  The ability to set individual per display video card 
gamma tables is a requirement for any system used for color critical work.
 
RandR 1.2 now has gamma setting functions and this will eventually replace 
those in the XFree86 VidMode extension.  It appears that nvidia will support 
randr 1.2 at some point in their drivers.  At least that is what I was told 
by nvidia support on the nvnews linux forum about 4 months ago.  This came at 
the end of a protracted thread about the twinview XFree86 VidMode extension 
issue that started about 4 months earlier.  And when that happens twinview 
becomes an option if everything works to specs (I'm not holding my breath).  
But when will that happen?   I have this feeling that nouveau will become a 
viable option before twinview does.

This also means rewritting my code for setting video card gamma tables to use 
randr calls when these are available.  This will have to happen at some point 
regardless of when nvidia delivers randr 1.2 support.  I would like to be 
able to test my application using the randr 1.2 gamma setting code sometime 
soon.  Does anyone know if the nv driver has randr 1.2 support yet? 

>
> > The other issue I have with nvidia-settings is that it
> > clobbers my video card gamma tables when ever it is run making my
> > displays, which were carefully calibrated using a EyeOne Display color
> > meter, not so calibrated anymore.
>
> You can use the '--no-config' commandline option to tell nvidia-settings
> to not upload the currently saved settings in the .rc file.

Yes that takes care of this problem.  Thanks.

snip

>
> If you could send me your complete X log, I could take a look.

Thanks for the offer but it appears that this is an issue with Xinerama and 
the fact that twinview is not ready for prime time where users are doing 
color critical work.

Hal