df showing ugly uuid for root device

I found that after upgrading debian to wheezy the df command was showing a long name for the root device instead of the real normal short name like /dev/sda1.

/dev/disk/by-uuid/4661950b-0d92-4a1d-9919-2b71eaa14189

I found this link very helpful in explaining the problem and giving a workaround.

Building a single kernel module on Debian.

I was trying to build snd-seq-oss.ko so I could run the old playmidi that requires OSS /dev/sequencer, but when I did the insmod I got a -1 "Invalid module format" and dmesg showed "snd_seq_oss: no symbol version for module_layout".

I found out the problem was that since I am building just the module not the kernel, I need the Module.symvers from the distro's kernel.  So the solution in this case was to install linux-headers-2.6.32-5-686 and copy the Module.symvers from there.

There's probably other ways to do it but that is what worked for me.  See steps below for future reference.

sudo -i

apt-get install linux-headers-2.6.32-5-686 linux-source-2.6.32

cd /usr/src

tar -jvxf linux-source-2.6.32.tar.bz2

ln -s linux-source-2.6.32 linux

cd linux

cp ../linux-headers-2.6.32-5-686/Module.symvers .

cp /boot/config-2.6.32-5-686 .config

   (modify .config as desired)

make oldconfig

make prepare

make modules_prepare

make SUBDIRS=scripts/mod

make SUBDIRS=path/to/module modules

Use right alt as Windows key in Debian Squeeze

My Thinkpad has no Windows key, so I was using a startup file with xmodmap commands to map my right alt to the Windows key (Super_L).

That worked great until I updated Debian to Squeeze. Then it would only work if I ran it manually after Gnome came up. I tried several startup scripts with different names including .gnomerc, but my settings just wouldn't stick.

So I decided it must be getting overridden by a later step, probably a step where it checks gnome-keyboard-properties settings and calls setxkbmap, so that resets anything you tried to do in a start-up script.

There is an option in gnome-keyboard-properties for "Left Alt is swapped with Left Win". That causes it to run setxkbmap -option altwin:swap_lalt_lwin I believe. That would work perfectly for me, except I want to map the right alt, not the left alt.

So finally, here is what I came up with (probably not the right solution, but it works). I edited all the files in /usr/share/X11/xkb/rules/ with swap_lalt_lwin in them and added a similar line/section called swap_ralt_lwin. Similarly I edited /usr/share/X11/xkb/symbols/altwin and added a section at the bottom for swap_ralt_lwin that works similar to the swap_lalt_lwin section.

Debian Lenny to Squeeze on Thinkpad T42

The good:

• Faster bootup.
• Very fast switching between X and a VT.
• Firefox 3.5 is much faster than 3.0.
• Most Thinkpad extra keys now work great out of the box.
• Cool desktop backgrounds.

The bad:

• X11 looked funny. Turns out no themes were installed. Had to install gnome-themes.
• Got a bunch of warnings from udev on bootup, coming from z60_xserver-xorg-input-wacom.rules, so I purged xserver-xorg-input-wacom.
• The ACPI hotkey events changed names, so some hooks I had set up in /etc/acpi/events stopped working until I updated the names.
• EmulateWheel setting in xorg.conf no longer works. xinput works. I installed gpointing-device-settings, which is a very convenient solution.
  
• Alt_R keycode is now 108 instead of 113.

The ugly:

• X wouldn't start. Turns out it was because gdm wasn't installed. Why did gdm get removed during upgrade? Maybe it wanted to replace it with gdm3? But it didn't install gdm3.
  

Debian Linux 5 (Lenny) on Thinkpad T42

I know it seems backwards, but I recently switched from Ubuntu to Debian on my old reliable Thinkpad T42 laptop. Here are some of the problems I encountered and tweaks I made to get it working nicely.

Back and forward keys, and right alt as windows key:
1. Set up .xinitrc
#!/bin/sh
xmodmap -e "keycode 113 = Super_L" # reassign Alt_R to Super_L
xmodmap -e "remove mod1 = Super_L" # make sure X keeps it out of the mod1 group
xmodmap -e "keycode 234 = XF86Back" # Back button.
xmodmap -e "keycode 233 = XF86Forward" # Forward button.
2. Add command to gnome session to run .xinitrc

Fix the "Access IBM" and "Alt-Space" keys:
1. Add to /etc/rc.local
# Dumb kernel drops the acpi_fakekey.
/usr/bin/setkeycodes e017 148 # (for the Access IBM button)
/usr/bin/setkeycodes 0082 192 # (for the Fn+SPACE combination)

Emulate mouse wheel in X with middle button:
1. Add these three lines to /etc/X11/xorg.conf in the "Configured Mouse"
InputDevice section:
Option "EmulateWheel" "true"
Option "EmulateWheelTimeOut" "200"
Option "EmulateWheelButton" "2"

Note: Lenny uses XServer 1.4.2, which does use HAL, but not as fully as 1.5 or something because I couldn't get it to work with a .fdi file.

Make Fn-F5 toggle just bluetooth, not wireless:
1. Copy bluetooth_toggle.sh to /usr/local/sbin/
2. Change the action line in /etc/acpi/events/ibm-wireless to:
action=/usr/local/sbin/bluetooth_toggle.sh

Make Fn-F7 toggle between LCD,TV,and TV+LCD
1. Copy video.sh to /usr/local/sbin/
- (borrowed heavily from this script.
2. Change the action line in /etc/acpi/events/ibm-videobtn to:
action=/usr/local/sbin/video.sh toggle
3. Enable Fn-F7 by modifying the options line in /etc/modprobe.d/thinkpad_acpi.modprobe to:
options thinkpad_acpi hotkey=enable,0xffffff experimental=1