Red Hat Bugzilla – Bug 121717
can't change screen resolution / HorizSync/VertRefresh not uncommented in xorg.conf
Last modified: 2007-11-30 17:10:41 EST
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Description of problem:
I installed FC2test3, rebooted and X config came up. I selected
1024x768, but GNOME came up with 800x600.
system-config-display only showed 800x600 and 640x480.
No chance to get it working with 1024x768 (even selected a default
monitor [1024x768] and edited xorg.conf - added "1024x768" for the
Graphics card: ATI Mach64VT
Monitor: Siemens Nixdorf MCM 1702
* ddcprobe returned bogus values:
Trying with card: ATI Mach64VT (264VT)
# kudzu --probe --bus=DDC
desc: "ATI Technologies Inc. MACH64VT"
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. install FC2test3
2. select 1024x768 in the X configuration
3. graphical login, KDE and GNOME comes up in 800x600
Actual Results: Couldn't change the screen resolution to 1024x768
It is reproducable no matter how often I run system-config-display,
but I haven't tried another install...
Expected Results: system-config-display should have at least the
option 1024x768 which I chose during the X configuration
I solved the problem by editing xorg.conf again and uncommenting the
lines for HorizSync and VertRefresh.
I believe it is a bug in system-config-display, since xorg.conf is
created by it.
I have the same problem. I had to manually uncomment the H&Vsync
options because my machines are on a KVM switch. The DDC probe
doesn't work, so I have to manually specify the monitor.
This would be a Bad Thing if this is going to be the default. Most
people at our company use KVM switch boxes, and I don't really want to
have to manually change the conf file on each installation.
Created attachment 99708 [details]
screenshot showing the double frame resulting from the bug
Same problem here, resulting in a double frame display, with the lower
half not sensitive to the mouse.
Taking a screenshot, reveals the hole desktop however, so I attach a
fotograph from my monitor. (iiyama vision master pro510)
The was correctly detected by the configurator.
Uncommenting the two Hsync en Vsync lines resolves the problem
The DDC probe doesn't seem to work with my notebook as well (Toshiba
Satellite Pro 6100: P4, Geforce 4 Go 420,1024x768 TFT panel)
Uncommenting the two Hsync en Vsync lines resolved the problem for me too.
This is due to libxf86config in xorg commenting these out by default
(see bug 120950)
I had the same problem on my notebook but xorg detected the right
resolution. Comparing /etc/X11/xorg.conf and /etc/X11/xorg.conf.backup
shows that the xorg.conf.backup has the Hsync and Vsync uncommented.
#cp /etc/X11/xorg.conf.backup /etc/X11/xorg.conf
Same problem with CyberBlade (Generic) and Iiyama VisionMaster
MF-8317. I routinely use 1024x768, which even works under that
glass-thingy OS. FC2 test 2 was able to use the same resolution.
I'm also using a KVM switch, but that should be irrelevant, since it
detected the video card correctly and I specified the monitor in Anaconda.
Firstboot gave me an option of 640x480 or 800x600. I figured I would
have to manually tweak the setting afterward, so I selected 800x600.
It booted into 640x480 instead. After manually editing the xorg.conf
file to specify 1024x768 it boots into 800x600.
I found similar behavior on the Sony Vaio PCG-SRX77P. The workaround
is to hand-edit the /etc/X11/xorg.conf and inform it gently, that the
DefaultDepth is 16 and change the Display settings to support 16-bit
resolution, something like the excerpt below.
Modes "1024x768" "800x600" "640x480"
# DefaultDepth 24
# SubSection "Display"
# Depth 24
# Modes "1024x768" "800x600" "640x480"
*** This bug has been marked as a duplicate of 120950 ***
Changed to 'CLOSED' state since 'RESOLVED' has been deprecated.