How to load a specific video driver in a separate X server?

[figure002]

I configured my Ubuntu system (12.10, 64bit) so that I'm able to start any application in a separate X server. Running games or for example XBMC in a separate X server has some major advantages. I can run an application in a separate X server as follows:

xinit /usr/bin/xbmc -- :1

I already managed to get sound working in the separate X server. The problem I'm having now is that when I'm in the separate X server, Ubuntu seems to load the wrong video driver. When, for example, I load XBMC in the main X server all works fine. But when I execute it in a separate X server, the graphics look ugly and are very slow too.

This happens on my laptop with an Intel HD Graphics 3000 chip (default driver). This problem does not occur on a different laptop with Ubuntu 12.10, an Nvidia GeForce G105M chip, and the proprietary Nvidia or nouveau driver.

I suspect that the wrong video driver is being loaded for the separate X server. I did get some clues from the command line. The command below was executed from the second X server:

serrano@saibot:~$ LIBGL_DEBUG=verbose xbmc
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/i965_dri.so
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: i965
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/swrast_dri.so
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/serrano/.drirc: No such file or directory.
Running DIL (3.22.0) Version
DtsDeviceOpen: Opening HW in mode 0
DtsDeviceOpen: Create File Failed
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/i965_dri.so
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: i965
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/swrast_dri.so
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/serrano/.drirc: No such file or directory.
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/i965_dri.so
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: i965
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/swrast_dri.so
libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/serrano/.drirc: No such file or directory.

I don't really know where to go from here. Help is much appreciated.

[figure002]

It wasn't until after I posed the above log that I noticed the "Permission denied" messages. This usually means insufficient privileges, so I did the following:

xinit -- :1

Then in the second X server:

sudo xbmc

And guess what, the graphics look as they should. I'm still confused why I'm getting these "Permission denied" messages. Could someone tell me how I can fix this? Having to execute regular programs as root is obviously not the right solution.

EDIT:

As a side effect of using 'sudo' in the above command sound no longer works properly in XBMC. Audio works until audio or a video is played. So this isn't a solution.

[figure002]

I found the solution to my problem on this blog post: https://kparal.wordpress.com/2013/02...ons-with-sudo/

To keep it short, I had to add myself to the 'video' group: sudo usermod -a -G video $USER
Which is similar to the way I enabled audio in separate X servers: sudo usermod -a -G audio $USER