Where - and how - does KDE decide what the resolution of my screens should be at log in?

I run "KDE Platform Version 4.14.2" under Debian on a Lenovo ThinkPad T430, and I have two monitors attached - one is the laptop screen, the other is an external one. Until this week it has worked fine; I have them working together as one display. Now, however, when I log in, the two screen are placed on top of each other, both display the same output - ie. I have two cursors, etc, and the resolution is something ridiculously low. I can change it in 'System settings', but only for the current session.

Looking online I see suggestions involving krandrrc or similar, but it looks like a hack to me, and since it was working before, it ought to be working now. I can probably fix it by reinstalling the whole system, but I would like to understand what is going on here.

krandrrc should be cruft, kscreen stores its stuff in ~/.kde/share/apps/kscreen/* resp. ~/.local/share/kscreen/* in KDE5 ("ps ax | grep kded", will either say kded4 or kded5) - you could inspect whether one of those files contains the "ridiculous low resolution" (aka VGA?)

If you're on KDE4 and have ~/.kde/share/config/krandrrc (or ~/.kde4/share/config/krandrrc), try to move it away.

You may also want to check /var/log/Xorg.0.log on whether you're accidentally using the VGA driver (which is the ultimate failsafe solution, if it's loaded, it should be unloaded and replaced by sth. "better")

Hi luebking,

Thank you for your insight. I don't think it is X - it used to work, and the fact that can manually reconfigure it to work suggests that the driver is loaded. I had a look in the directories you suggested and found:

Code: Select all

# ll
total 16
-rw-r--r-- 1 root root 569 Jun 16  2014 79dfb09bc5582b1f5cef8abc1e0dd1c4
-rw-r--r-- 1 root root 275 Jun 30  2014 8f27e66f2df16668f11cfb00c42a0786
-rw-r--r-- 1 root root 569 Jun 30  2014 bee96b4b87370152c17daf2adf37fbfa
-rw-r--r-- 1 root root 568 Jun 30  2014 e607651b3fedd51055802845076045ed


And they contain:

Code: Select all

[ { "enabled" : true, "id" : "722eec487e94e2b20c9b49d44ef22153", "metadata" : { "fullname" : "xrandr-SyncMaster-H9XB703398", "name" : "HDMI3" }, "mode" : { "refresh" : 59.9502, "size" : { "height" : 1200, "width" : 1920 } }, "pos" : { "x" : 0, "y" : 0 }, "primary" : false, "rotation" : 1 }, { "enabled" : true, "id" : "f08263aa1c01c3c24dc37408b48d3319", "metadata" : { "fullname" : "xrandr-unknown", "name" : "LVDS1" }, "mode" : { "refresh" : 60.007, "size" : { "height" : 900, "width" : 1600 } }, "pos" : { "x" : 1920, "y" : 0 }, "primary" : false, "rotation" : 1 } ]
[ { "enabled" : true, "id" : "f08263aa1c01c3c24dc37408b48d3319", "metadata" : { "fullname" : "xrandr-unknown", "name" : "LVDS1" }, "mode" : { "refresh" : 60.007, "size" : { "height" : 900, "width" : 1600 } }, "pos" : { "x" : 0, "y" : 0 }, "primary" : true, "rotation" : 1 } ]
[ { "enabled" : true, "id" : "9adecef9277f8d1737883f561a076644", "metadata" : { "fullname" : "xrandr-DELL P2412H-TTMDG34C1A1U", "name" : "HDMI3" }, "mode" : { "refresh" : 60.0, "size" : { "height" : 1080, "width" : 1920 } }, "pos" : { "x" : 0, "y" : 0 }, "primary" : false, "rotation" : 1 }, { "enabled" : true, "id" : "f08263aa1c01c3c24dc37408b48d3319", "metadata" : { "fullname" : "xrandr-unknown", "name" : "LVDS1" }, "mode" : { "refresh" : 60.007, "size" : { "height" : 900, "width" : 1600 } }, "pos" : { "x" : 1920, "y" : 0 }, "primary" : false, "rotation" : 1 } ]
[ { "enabled" : true, "id" : "f08263aa1c01c3c24dc37408b48d3319", "metadata" : { "fullname" : "xrandr-unknown", "name" : "LVDS1" }, "mode" : { "refresh" : 60.007, "size" : { "height" : 900, "width" : 1600 } }, "pos" : { "x" : 1920, "y" : 0 }, "primary" : false, "rotation" : 1 }, { "enabled" : true, "id" : "4414d0a4e31d39abb2f6034902b070cd", "metadata" : { "fullname" : "xrandr-DELL P2412H-TTMDG34C1A1U", "name" : "VGA1" }, "mode" : { "refresh" : 60.0, "size" : { "height" : 1080, "width" : 1920 } }, "pos" : { "x" : 0, "y" : 0 }, "primary" : false, "rotation" : 1 } ]


This looks a lot like python to me, BTW, but I could use a manual for what it means. So, what is listed here is 1 line from each of the four files, and what each line tells corresponds to what I can see in settings, where HDMI3 has a max resolution of 1920x1200 and LVDS1 is 1600x900. What I don't quite understand is why there are four files, all vaguely similar; can I just delete them and then the system will create new ones - and all will be good?

Also, I don't understand why it suddenly stopped working - something like 2 weeks ago I suddenly found several things acting strange; my VM (virtualbox) wouldn't start because /usr didn't have the right permissions, my VPN couldn't start because /etc/network/interfaces had lost the network card and only listed loopback, and this problem, where my screens sort of work, but aren't initialised correctly.

Those files reflect the various setups you had, so that when you restore a hardware state, the previous setup (position, rotation, resolution, primary, ...) can be restored.

=> You can delete those files anytime.

Python is a whitespace driven language (ie. the amount of leading whitespace controls the code flow) - so this is certainly anything *but* python
I'd say the format is JSON.

> I don't understand why it suddenly stopped working
At least the presented configurations do not explain a "unified" setup.

Since there're two different external outputs listed (Samsung & Dell): did one of them enter the stage when the trouble started? Is your current external output in this list?

Did you check "xrandr -q" on what the "ridiculous low resolution" actually is?
Could also be that "somthing"™ tries to use a resolution common to the outputs (since they also operate in "cloned" or "unified" mode) - eg. XGA?