Ubuntu Wiki

For hard bugs the analysis phase is the most important, and most challenging part of bug work. Depending on how the bug is behaving, there are multiple directions to investigate the issue. Here's some different approaches:

Common Problems

General Issues

• Glossary - Common error messages and terminology

• High CPU usage issues

• High memory usage issues

• Suspend and Resume issues

• Program received an X Window System error

• X Transitions - Explanation for "installing xserver-xorg-core would break existing software"

Display Issues

• Video driver detection

• Monitor detection

• Resolution detection

• Freeze issues

• Backlight issues

• Blank Screen on startup issues

• 3D / GLX corruption and other issues

• Fonts displayed way too big

• Intel graphics performance issues

• i855 is Unsupported - Explanation of why i845, i855, i865, etc. chips aren't supported

Input Issues

• Multimedia hotkey problems

• Keyboard detection

• Touchpad detection

Troubleshooting Techniques

Booting

• Boot Options

• Debugging Kernel Boot Problems

• Non-Graphical Booting - Running X manually, without a display manager (like lightdm, kdm, gdm...)

• Wireless Without X - How to get a wireless network connection without X.

• Direct Wired Without WAP - How to connect two laptops with direct ethernet cord.

Crashes and Freezes

• X Backtracing - How to collect a backtrace for an X crash

• X Crash Fixing - How to fix X crashes

• Interpreting GPU Dumps - Ringbuffers, batchbuffers, and the meaning of intel_gpu_dump output

• Valgrind - Debugging memory leaks

Other Techniques

• X Bisecting - Using bisection techniques to solve regressions or backport fixes

• X/Testing/Touch - Touchscreen and multi-touch testing

• X Quirks - Fixes for some common hardware-specific issues

• Device Tree

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CategoryDebugging