Monthly Archives: March 2011

Debian, Linux

Debian 6 (Debian Squeeze) & Debian 7 (Debian Wheezy) reboot… doesn’t.

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Someone made kexec-tools handle reboot requests by default seemingly. This allows the system to skip BIOS/POST etc and just drop to a minimal runlevel and start a kernel again.

This is great if you only have debian on your system and particularly great if you spend a lot of time changing kernels – when you issue reboot, or shutdown -r now (etc) kexec-tools intercepts the command and does a warm-restart rather than resetting the machine cold – if you don’t need to, why wait through all the BIOS checks, bootroms, etc, right?

Except some of us reboot because we want to change OS. I’d argue that it should perhaps be the default behaviour to cold-reboot (and the installer could, perhaps, ask!) or that KDE should have a button for “warm restart” and one for “cold reboot” or whatever, but anyway.

If you want to make reboot actually reboot the system you’ll want to:

# dpkg-reconfigure kexec-tools

And tell it to not use kexec-tools to handle reboots. If you’re never going to want kexec-tools, you can probably uninstall it using apt, but I just disabled it. It’s useful on the odd occasion I do want to just upgrade the kernel to enable it, reboot, and disable it again, I suppose.

Some SEO, perhaps?

Debian 6 Squeeze won’t reboot
Debian 6 Squeeze reboot doesn’t go to grub
Debian 6 Squeeze reboot dualboot
Debian 7 Wheezy won’t reboot
Debian 7 Wheezy reboot doesn’t go to bios

Debian, Linux

Debian 6 (Debian Squeeze) KDE4 Override Screen Resolution

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Everything you needed to know about manually overriding incorrectly probed screen resolutions but nobody thought to write down, seemingly:

$ xrandr -q
Screen 0: minimum 320 x 200, current 3600 x 1080, maximum 8192 x 8192
DVI-I-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 477mm x 268mm
   1920x1080      60.0*+
   1600x1200      60.0  
   1680x1050      60.0  
   1400x1050      60.0  
   1280x1024      75.0     60.0  
   1440x900       59.9  
   1280x960       60.0  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        72.8     75.0     66.7     60.0  
   720x400        70.1  
DVI-I-2 connected 1680x1050+1920+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0  
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9  
   1680x1050      60.0*

This output shows what xrandr has detected. In my case, DVI-I-2 wasn’t showing the 1680×1050 resolution I needed. It’s there now because this output is from after I made my modifications.

$ xrandr --addmode DVI-I-2 "1680x1050"

Was all it took.

Sadly, of course, this is all lost on reboot, despite making changes in the System Settings/Display panel and saving them as default – because even though my screen alignment settings were saved in $HOME/.kde/share/config/krandrrc, the mode 1680×1050 isn’t remembered as being valid for my screen.

Because krandrrc contains a config element like this:

[Display]
ApplyOnStartup=true
StartupCommands=xrandr --output "DVI-I-1" --pos 0x0 --mode 1920x1080 --refresh 60\nxrandr --output "DVI-I-2" --pos 1920x0 --mode 1680x1050 --refresh 59.9543

I simply elected to try adding:

xrandr --addmode DVI-I-2 "1680x1050"

To the front end of StartupCommands, like so:

[Display]
ApplyOnStartup=true
StartupCommands=xrandr --addmode DVI-I-2 "1680x1050"\nxrandr --output "DVI-I-1" --pos 0x0 --mode 1920x1080 --refresh 60\nxrandr --output "DVI-I-2" --pos 1920x0 --mode 1680x1050 --refresh 59.9543

On reboot, my screen resolution is correctly set, and my dualhead config works as expected. Now I just need to remember never to change my screen settings again, or be prepared to make that change again.

Some SEO, hopefully:

KDE4 Manual Resolution
KDE4 Override Screen Resolution
KDE4 Incorrect Screen Resolution