How to detect and configure an output with xrandr?
- by ysap
I have a DELL U2410 monitor connected to a Compaq 100B desktop equipped with an integrated AMD/ATI graphics card (AMD E-350). The installed O/S is Ubuntu 10.04 LTS.
The computer is connected to the monitor via the DVI connection.
The problem is that I cannot set the desktop resolution to the native 1920x1200. The maximum allowed resolution is 1600x1200.
Doing some research I found about the xrandr utility. Unfortunately, when trying to use it I cannot configure it to the required resolution. First, it does not report the output name (which supposed to be DVI-0), saying default instead. Without it I cannot use the --fb option.
The EDID utility seems to identify the monitor well. Here's the output from get-edid:
# EDID version 1 revision 3
Section "Monitor"
# Block type: 2:0 3:ff
# Block type: 2:0 3:fc
Identifier "DELL U2410"
VendorName "DEL"
ModelName "DELL U2410"
# Block type: 2:0 3:ff
# Block type: 2:0 3:fc
# Block type: 2:0 3:fd
HorizSync 30-81
VertRefresh 56-76
# Max dot clock (video bandwidth) 170 MHz
# DPMS capabilities: Active off:yes Suspend:yes Standby:yes
Mode "1920x1200" # vfreq 59.950Hz, hfreq 74.038kHz
DotClock 154.000000
HTimings 1920 1968 2000 2080
VTimings 1200 1203 1209 1235
Flags "-HSync" "+VSync"
EndMode
# Block type: 2:0 3:ff
# Block type: 2:0 3:fc
# Block type: 2:0 3:fd
EndSection
but the xrandr -q command returns:
Screen 0: minimum 640 x 400, current 1600 x 1200, maximum 1600 x 1200
default connected 1600x1200+0+0 0mm x 0mm
1600x1200 0.0*
1280x1024 0.0
1152x864 0.0
1024x768 0.0
800x600 0.0
640x480 0.0
720x400 0.0
When I try to set the resolution, I get:
$ xrandr --fb 1920x1200
xrandr: screen cannot be larger than 1600x1200 (desired size 1920x1200)
$ xrandr --output DVI-0 --auto
warning: output DVI-0 not found; ignoring
How can I set the screen resolution to 1920x1200?
Why doesn't xrandr identify the DVI-0 output?
Note that the same computer running Ubuntu version higher than 10.04 detects the correct resolution with no problems. On this machine I cannot upgrade due to some legacy hardware compatibility problems.
Also, I don't see any optional screen drivers available in the Hardware Drivers dialog.
----
UPDATE:
following the answer to this question, I got some advance. Now the required mode is listed in the xrandr -q list, but I can't switch to that mode. Using the Monitors applet (which now shows the new mode), I get the response that:
The selected configuration for displays could not be applied. Could not set the configuration to CRTC 262.
From the command line it looks like this:
$ cvt 1920 1200 60
# 1920x1200 59.88 Hz (CVT 2.30MA) hsync: 74.56 kHz; pclk: 193.25 MHz
Modeline "1920x1200_60.00" 193.25 1920 2056 2256 2592 1200 1203 1209 1245 -hsync +vsync
$ xrandr --newmode "1920x1200_60.00" 193.25 1920 2056 2256 2592 1200 1203 1209 1245 -hsync +vsync
$ xrandr -q
Screen 0: minimum 640 x 400, current 1600 x 1200, maximum 1600 x 1200
default connected 1600x1200+0+0 0mm x 0mm
1600x1200 0.0*
1280x1024 0.0
1152x864 0.0
1024x768 0.0
800x600 0.0
640x480 0.0
720x400 0.0
1920x1200_60.00 (0x120) 193.0MHz
h: width 1920 start 2056 end 2256 total 2592 skew 0 clock 74.5KHz
v: height 1200 start 1203 end 1209 total 1245 clock 59.8Hz
$ xrandr --addmode default 1920x1200_60.00
$ xrandr -q
Screen 0: minimum 640 x 400, current 1600 x 1200, maximum 1600 x 1200
default connected 1600x1200+0+0 0mm x 0mm
1600x1200 0.0*
1280x1024 0.0
1152x864 0.0
1024x768 0.0
800x600 0.0
640x480 0.0
720x400 0.0
1920x1200_60.00 59.8
$ xrandr --output default --mode 1920x1200_60.00
xrandr: Configure crtc 0 failed
Another piece of info (if it helps anyone):
$ sudo lshw -c video
*-display UNCLAIMED
description: VGA compatible controller
product: ATI Technologies Inc
vendor: ATI Technologies Inc
physical id: 1
bus info: pci@0000:00:01.0
version: 00
width: 32 bits
clock: 33MHz
capabilities: pm pciexpress msi bus_master cap_list
configuration: latency=0
resources: memory:c0000000-cfffffff(prefetchable) ioport:f000(size=256) memory:feb00000-feb3ffff
