Dualhead, 16:10 and XRandR

With my move to Gnome I decided to try out again the graphical login. I used to use standard console login before because KDM lacked too many features, and while for some time I kept using GDM, it just didn’t feel right. Unless I was going to just do some system administration, or testing PAM, the only command I was going to type was startx, followed by sudo shutdown -h once I was done.

To do so, I had to give up keychain, at least for inserting the private key’s passphrase. Instead of using that, I decided to change my PAM setup to use pam_ssh (and this is also what brought me to plan removal of pam_ssh_agent .. I just remembered I forgot to add that to the Gentoo Calendar! — done!), so that instead of typing my password and my SSH key passphrase, I just have to type in my passphrase at login and I’m done. The nice thing is that the standard Unix password is also accepted, so I can use that to take me out of the lock screen that Gnome applies when I walk away from the system, which is much shorter.

Again, I will probably put up a request for an electronic ID card next september and consider using a smartcard reader (I I wonder if I can use old, invalid, credit cards as smartcards too, once they are formatted).

So okay, I’ll write at another time about pam_ssh, it’s not what I’d like to write about right now.

With GDM I’m having one problem: my current setup is a dualhead, with a 16:10 monitor (and a 4:3) and using XRandR 1.2 (radeon driver). I have the screen disposition set up in my xorg.conf, but I’m not able to set the proper mode for the 16:10 monitor in the configuration file. If I set PreferredMode in xorg.conf, X11 refuses to start, without any apparent error either.

So for now I’m running at the session manager level two xrandr commands to set up properly the screens, but there is one problem: synergys does not seem to be expecting the geometry of the screens to change, so it still wraps my pointer out on the coordinates where it should have wrapped before the xrandr fixes.

I should probably see to try the latest masked version of xorg, and check if it works there. Although I think Synergy should have considered the case of changing screen layout. Maybe one day it will be rewritten using XCB and it will consider that problem too ;)

Oh yeah I should be writing about XCB too…

2 thoughts on “Dualhead, 16:10 and XRandR

  1. PreferredMode is a decoy. On all my systems, X is actually *less* likely to pick the correct resolution by default if you specify a PreferredMode option.Also, my 16:10 monitor is paired with a 5:4 monitor on an Intel chipset. The 16:10 shows up in the wrong mode by default, and the 5:4 will *never* run in 1280×1024 (its native res). I’m already running all the Xorg pre-release packages.Good luck and I’ll watch your blog to see if you figure out the problem! :-)


  2. Actually it works now with 1.5 pre-release, but I had to set PreferredMode to both the 16:10 and the 5:4 monitors so that they could write. But now it works perfectly without running xrandr at all.


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