Red Hat Bugzilla – Bug 434149
DPI wrong when using DualHead option
Last modified: 2013-11-05 14:18:24 EST
Description of problem:
While trying to use the DualHead option with a nVidia Quadro FX 330, the DPI
calculated is wrong and pixmaps are drawn too large.
dimensions: 2560x1024 pixels (380x313 millimeters)
resolution: 171x83 dots per inch
when without the DualHead option I get:
dimensions: 1280x1024 pixels (382x313 millimeters)
resolution: 85x83 dots per inch
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Connect two screens to a Dell Precision 470
2. Add 'Option "DualHead"' to config
4. check xdpyinfo or open firefox
See above and Xorg.0.log, soon to be attached.
When using the DualHead option the width of both screens should be added, or at
least the width of the first screen doubled.
I can work around this by running `startx -- -dpi 85` but I don't know what
option to set in xorg.conf to do this. I tried using the "DisplaySize" option,
but that did not work.
Created attachment 295623 [details]
/var/log/Xorg.0.log with DualHead option enabled
This probably should be a separate bug but I noticed that power management
doesn't work on the second head either. The first head will power down while
the second stays on.
I see this bug on dualhead on an ati card too. DPI is off by a factor of 2 with 2 identical monitors in use. Seen on:
No further X updates are planned for RHEL5.