ubuntu-x-swat team mailing list archive

[Martin Olsson <mnemo@xxxxxxxxxx>]

I have no really good solution for this but let me at least give you
some more information, maybe you can use that to debug the issue
further.

I think, when compiz is running all windows are rendered as 3D textures.
In additional, I think compiz also flips itself into INDIRECT rendering
mode (which means 3D accel is used but all drawing commands are sent
using AIGLX from the app to the X server and then the X server is the
process that calls the kernel 3D API). Compiz needs the openGL
texture_from_pixmap to be available.

In general, when DIRECT rendering is used (you can tell by running
"glxinfo" and grepping the out for "direct"), then you can force a 3D
app to use software rendering by making sure that the
LIBGL_ALWAYS_SOFTWARE=1 environment variable is set for that process.
For example:

    LIBGL_ALWAYS_SOFTWARE=1 glxgears

...will usually give you much lower FPS etc.

You can also control whether DIRECT/INDIRECT rendering should be used
with the env var:

    LIBGL_ALWAYS_INDIRECT=1 ./some_app

...however note that if you do this, then the 3D rendering will be done
in the X server so if you want to combine that with SOFTWARE rendering
then that LIBGL_ALWAYS_SOFTWARE=1 needs to be set inside the X server
afaik.

Finally, there is also:

    LIBGL_DEBUG=verbose glxgears

...which allows you to analyze 3D operations in detail.

---

I don't think these environment variables will help you much for
OpenOffice though. Basically OO should just work, I hope we can get the
bug fixed instead.

Oh and one more thing. The driver option "NoAccel" is like a sledge
hammer that turns of _everything_. You might be able to keep some of the
3D accelerated operations and still don't get crashes. Understand which
part of the 3D acceleration that is causing the bug might prove useful
in narrowing down the bug location.

To test with partial 3D accel enabled for the radeon driver, see the
manual page "man radeon". I would in particular recommend that you try
using the radeon driver without noaccel but _with_ exactly one of these
options at a time:

	Option "EXANoComposite"
	Option "EXANoDownloadFromScreen"
	Option "EXANoUploadToScreen"

If you can repro the bug with DownloadFromScreen then we know that the
bug is likely to be hiding in that part of the radeon driver. Also
trying different, more recent versions of the driver is useful. For
example, if you boot the karmic alpha live CD and the bug is not
present, then it's likely that it got fixed somewhere between these
versions and then we might be able to search the source diff between
these versions for relevant clues.

-- 
[R420] system freezes when starting openoffice writer
https://bugs.launchpad.net/bugs/371296
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