Bugs should be filed in this projects' issue tracker. Make sure to include the following information:
A clear subject describing the issue.
Steps to reproduce the issue.
How often does the steps listed above trigger the issue? For example: always, 1 out 3 times.
Which platforms and features are affected (if you can).
The following information about your system:
- -- system architecture: ("uname -m")
- -- kernel version: ("uname -r"). Again, please consider using latest drm-tip from http://cgit.freedesktop.org/drm-tip
- -- Linux distribution
- -- Machine or mother board model (use dmidecode if needed)
- -- Display connector: (such as HDMI, DP, eDP, ...)
- A full dmesg with debug information and/or a GPU crash dump:
To obtain a dmesg with debug information, add
drm.debug=0x1e log_buf_len=1Mto your kernel command line, then reboot and reproduce the issue again. Make sure to attach the full dmesg all the way from boot.
In the case of a GPU hang, dmesg will contain a "GPU crash dump saved to /sys/class/drm/card0/error" message. The contents of that file are crucial to debugging the issue. Note that the contents of that file are generated by the kernel when it is read, so it will appear to have zero bytes. Reading the file contents with cat will produce the expected result. For example, use
$ cat /sys/class/drm/card0/error | bz2 > error.bz2
Note that a new bug is preferred over adding your GPU crash dump to an already open bug. Most often the cause for the GPU hangs are different, and it is easy for the developers to mark bugs as duplicate.
Other attachments if relevant:
- screenshot or photo (a picture is worth a thousand words);
- output of "xrandr --verbose" for display mode issue;
- intel_reg_dumper output (see the guide) and VBIOS dump (see the guide) for display issues;
- for GPU hang, get the last batch buffer (see the guide);
- for suspend/resume problems, refer to the guide.
When reporting a regression bug, this is critical that both Good commit (where issue is not occuring) and Bad commit (where issue is occuring) are provided in the bug description because it will argue on the fact this is regression. The following labels are used to document the state:
- regression : indicates this defect is a regression and both Good & Bad commits are provided,
- bisect_pending : indicate that a bisect is not yet done and therefore result is pending,
- bisected : indicates that a bisect was done and result is available in bug comments.
Developers may ask for additional information. In that case, the issue label "Needs Information" will be set.