Screen stuck at suboptimal resolution due to virtual size

[Soren Hansen]

This bug report is based on anectodal evidence gathered when helping
someone else get back to his proper resolution on his laptop, but I
belive it's accurate.

He'd been playing around with the TV-Out port, and now his screen was
stuck at a resolution of 1360x768, so it didn't fill the screen (which
has a physical resolution of 1440x900). It turned out that his xorg.conf
specified a virtual resolution of 2048 by 768, so apparantly XRANDR
couldn't offer resolutions with a height of more than 768 pixels.

I imagine this happened because he at some point had the laptop and the
TV-Out both at 1024x768, side by side, and tried to apply it, at which
point this setting would get written to xorg.conf.

The core problem here, I think, is that there's no obvious way to revert
the setting in xorg.conf, and xrandr doesn't even list the resolutions
that exceed the virtual resolution, so gnome-display-properties can't
even know that there's a higher resolution that is not being shown.

  affects ubuntu/gnome-control-center

[Alberto Milone (albertomilone)]

The attached debdiff should reduce the problem.

When a virtual resolution smaller than 2048x2048 is required, 2048x2048 is set instead of the required virtual resolution. Usually 2048x2048 is the highest virtual resolution which doesn't break direct rendering.

If a bigger virtual resolution is required (say 3000x3000) this resolution will be set.

Here's how you can test the new behaviour:

:~$ python /usr/share/screen-resolution-extra/policyui.py 2024x768

:~$ grep Virtual /etc/X11/xorg.conf
  Virtual 2048 2048

:~$ python /usr/share/screen-resolution-extra/policyui.py 3000x3000
:~$ grep Virtual /etc/X11/xorg.conf
  Virtual 3000 3000

[Launchpad Janitor (janitor)]

This bug was fixed in the package screen-resolution-extra - 0.9

---------------
screen-resolution-extra (0.9) karmic; urgency=low

  * policyui.py:
    - Normalise docstrings in checkVirtual().
    - Remove computeVirtual() and compareFrameBuffer() as they were not used
      since gnome-control-center already checks the available front buffer size.
    - Add the optimal_virtual_resolution attribute set to [2048, 2048] (usually
      the highest virtual resolution which doesn't break direct rendering) to
      the BootWindow class and make sure that, if the required resolution is
      lower than optimal_virtual_resolution, the latter is used instead of the
      former (LP: #412948).

 -- Alberto Milone <email address hidden> Thu, 13 Aug 2009 14:14:03 +0200