Fixing the Slackware KDE4 Screen Resolution Issue

Author: Steven Neiland

Warning: This blog entry was written two or more years ago. Therefore, it may contain broken links, out-dated or misleading content, or information that is just plain wrong. Please read on with caution.

When you install slackware one of the annoying issues with it is that xorg / kde is not configured automatically. This means that many people will have screen problems when they first startx. Further when you do change your screen resolution in kde4 it is not remembered when you restart. Fortunately this is actually pretty simple to fix in most cases.

Step 1: Run Xorgsetup

As xorg is not configured by default the first step in fixing kde is to run "xorgsetup". This handy utility will try to auto detect your hardware and write the xorg config file.


During the setup process your will be asked to select a color depth. I chose 24bit. Make a note of your choice for later.

Step 1 Alternative: Manual xorg configuration using xorgconf

For those of you who prefer a little more control you can use "xorgconf" to setup the config file. This is a question and answer type system which requires you to have more intimate knowledge of your hardware.

Step 2: Edit the Xorg.conf File

At this stage the majority of xorg issues should be resolved... however for those still experiencing problems trying to get kde to remember your chosen screen resolution we need to take the additional step of editing the "xorg.conf" file.

vi /etc/X11/xorg.conf

Edit the Monitor Section

When the editor opens we need to check two sections. The first is the monitor section. Scroll down the file until you see the monitor section which should have been automatically created by the xorgsetup command.

Check to make sure that the "HorizSynch" and "VertRefresh" values have been filled in. If not you should look them up from your monitors manufacturers website. For reference here is my monitor section for my LG monitor.

Section "Monitor"
#DisplaySize 510 290 # mm
Identifier "Monitor0"
VendorName "GSM"
ModelName "W2361"
HorizSync 30.0 - 83.0
VertRefresh 56.0 - 75.0
Option "DPMS"

Edit the Screen Section

The last section we need to edit is the section which deals with the selected screen resolution. Here we need to check three things.

  • Firstly that the Monitor selected matches the "Identifier" of the monitor from the monitor section above.
  • Second that the "DefaultDepth" is set to the value we chose when we ran xorgsetup.
  • Finally that the various screen modes have been supplied for the relevent "Display" subsection for our selected Depth

As a reference here is my "Screen" section. Note that I have "Monitor0" set for my monitor as per my monitor section, a "defaultDepth" of 24 (24-bit) and three "Modes" in the display subsection for depth 24.

Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 1
SubSection "Display"
Viewport 0 0
Depth 4
SubSection "Display"
Viewport 0 0
Depth 8
SubSection "Display"
Viewport 0 0
Depth 15
SubSection "Display"
Viewport 0 0
Depth 16
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1280x1024" "1024x768" "800x600"

Thats it, now when you startx, kde should load with your desired screen resolution.

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