Limited Resolution Choices in Xrandr with External Monitor on Hotplug

cram869 · 05-05-2010, 09:46 PM

I am running Fedora 12 on a T400 Thinkpad. When connector my external monitor prior to powering on the computer or if I restart it, I get a lot of resolution choices from xrandr. See below.

Code:

$ xrandr
Screen 0: minimum 320 x 200, current 1440 x 900, maximum 8192 x 8192
LVDS1 connected 1440x900+0+0 (normal left inverted right x axis y axis) 303mm x 190mm
   1440x900       60.0*+   50.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 connected (normal left inverted right x axis y axis)
   1024x768       85.0 +   85.0     75.1     75.0     70.1     60.0  
   1856x1392      60.0  
   1792x1344      60.0  
   1920x1200      59.9  
   1600x1200      85.0     75.0     70.0     65.0     60.0  
   1680x1050      84.9     74.9     60.0  
   1400x1050      85.0     74.9     60.0  
   1280x1024      85.0     75.0     60.0  
   1440x900       84.8     75.0     59.9  
   1280x960       85.0     60.0  
   1360x768       60.0  
   1280x800       84.9     74.9     59.8  
   1152x864       75.0  
   1280x768       84.8     74.9     59.9  
   800x600        85.1     72.2     75.0     60.3     56.2  
   848x480        60.0  
   640x480        85.0     75.0     72.8     60.0     59.9  
   720x400        85.0     70.1  
   640x400        85.1  
   640x350        85.1  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP3 disconnected (normal left inverted right x axis y axis)

However, if I do not have the external monitor connected on boot and hotplug it after I am started up, I only get a few resolution choices -- all of them too low to work for me.

Code:

$ xrandr
Screen 0: minimum 320 x 200, current 2464 x 900, maximum 8192 x 8192
LVDS1 connected 1440x900+0+0 (normal left inverted right x axis y axis) 303mm x 190mm
   1440x900       60.0*+   50.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 connected 1024x768+1440+0 (normal left inverted right x axis y axis) 352mm x 264mm
   1024x768       60.0* 
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP3 disconnected (normal left inverted right x axis y axis)

Is there some daemon I need to restart to detect the monitor resolutions correctly, or is there a module I can reload?

There seem to several variables to reproducing the behavior. If I restart without the laptop without the monitor plugged in, log in, and then, plug the monitor in with the monitor powered on prior to plugging, all resolutions are detected properly. However, if I plug the monitor in with it powered off, then power it on, I only get the few options shown in above. Once I get the reduced number of options, it seems to stay that way till I restart regardless of how I unplug the monitor.

I have found a work-around by just forcing the modes with xrandr --newmode and xrandr --addmode, but I would much rather have the modes autodetected.

Thanks,
Michael

tvynrylan · 06-01-2010, 07:24 PM

You and me both.

I don't have an answer for you, but I can relate my experience.

My laptop is a Dell Inspiron 1720 purchased about two years ago. It is running an nVidia GeForce 8800 GT. I get a similar behavior to the one you describe, albeit with even fewer resolutions. I also observe the strange okay-if-I-booted-with-a-monitor behavior, although this is not useful to me as I find myself connecting to a variety of projectors.

I found that using the proprietary nVidia blobs and the nvidia-settings tool got me some of the distance I want. nvidia-settings can properly detect the other screens and I can make use of them via TwinView. This is a messy process, however, and fouls up xrandr something awful. Furthermore, I can only get mostly correct behavior using xrandr 1.3; xrandr 1.2 tended to form one large rectangle due to its inability to involve multiple screens in one X display.

Good luck!