Identifying if the issue is a bug or not

If you aren't sure if you have encountered a software bug in Ubuntu, then you would want to seek help in determining if the issue is a bug or not from here.

If you have confirmed the issue is a bug, please read on.

Determining which type of bug you have

Not all bugs where X seems to be the root cause are in fact an X related bug. Hence, here is documentation on potential root causes:

Booting

• Boot Options

• Debugging Kernel Boot Problems

Display Issues

• 3D / GLX corruption and other issues

• Backlight issues

• Blank Screen on startup issues

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

• Fonts displayed way too big

• Freeze issues

• Intel graphics performance issues

• Monitor detection

• Resolution detection

• Video driver detection

General Issues

• Glossary - Common error messages and terminology

• High CPU usage issues

• High memory usage issues

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

• Program received an X Window System error

• Suspend and Resume issues

Input Issues

• Keyboard detection

• Multimedia hotkey problems

• Touchpad detection

Reporting a confirmed X bug to Launchpad

Initial filing of the report

First, please install the package xdiagnose.

Next, ensure you click the Yes button for attaching additional debugging information after running the following via a terminal:

ubuntu-bug xorg

Include developer information in your report

One will want to answer the following questions in order for a developer to address the issue:

• Does the report include debugging information from the relevant article relating to the reported issue?
• Is this a regression?
• Does this happen in the latest version of Ubuntu?
• Does this happen in the latest version available from upstream?

Debugging techniques

• 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

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

• Valgrind - Debugging memory leaks

Other Techniques

• Device Tree

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

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

Triaging and tagging X bugs

Please see here for more on triaging X bugs, and here for tagging.

Fixing an X crash

• For more on this, please see here.

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

Other Resources

• Video Resources at help.ubuntu.com

• For installing fglrx or nvidia proprietary drivers.

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CategoryDebugging