The problem#

I recently replaced my old Nvidia graphics card with a newer one. Upon booting up, I ran glxgears to test that 3D graphics were working properly and got an error like

X Error of failed request:  BadWindow (invalid Window parameter)
 Major opcode of failed request:  155 (NV-GLX)
 Minor opcode of failed request:  4 ()
 Resource id in failed request:  0x1200003
 Serial number of failed request:  34
 Current serial number in output stream:  34

The solution#

Either delete /etc/X11/xorg.conf or edit it and remove (or comment out) the "Files" section; that is, the lines

Section "Files"
    ...
EndSection

The problem#

Recently I ran a game¹ and instead of the expected music, got distorted noise. At first I thought there was something physically wrong with my speakers or the connection to them, but running any other program resulted in normal sound, albeit mixed with the distorted sound of the game. Even more strangely, changing the volume in the game changed the volume of the distorted noise, implying the game was in fact generating the right thing but it was being misinterpreted, so the culprit was neither the game nor the sound driver but somewhere in between them.

As I had recently set up PulseAudio², I suspected it was to blame. I opened up pavucontrol to find the game omitted from the list of applications producing sound, which suggested the problem was caused by the game trying to use some way to produce sound that PulseAudio was not capturing.

The solution#

The short version is that the problem was solved by restarting PulseAudio:

$ killall -9 pulseaudio

The problem#

I was modifying a screensaver written using SDL and noticed that sometimes there were many instances of it left running, even after unlocking the screen. Another bug was causing the screensaver to use 100% CPU, resulting in it using up all of my processing power just for a simple screensaver.

The solution#

Make the program exit immediately when it receives a SIGTERM signal by including the function

void exitImmediately(int sig) {
    abort();
}

and making the SIGTERM signal handler call it:

signal(SIGTERM, exitImmediately);