[ubuntu-x] Jaunty -intel defaults

Bryce Harrington bryce at canonical.com
Thu Mar 26 23:00:01 GMT 2009

Thank you everyone who has tested UXA, we've collected a lot of data
which helps make an informed decision regarding this new technology:


It is a shame that even with the fixes provided by the 2.6.3 -intel
many people are still seeing various lockups, crashes, and problems with
UXA enabled vs. with the default EXA, because many people see very
tangible performance benefits from it.

However, performance at the cost of increased freezes/crashes does not
seem to be a very wise trade for Ubuntu.


Some FAQ's that have already come up a lot:
Q: What about people who find non-UXA -intel unusable?

A: We're providing UXA as an opt-in experimental option for users who
   are comfortable with the stability issues, and will be documenting
   its availability in the release notes.

Q: Could UXA be limited to just the chips it works well on?

A: No.  It seems for every person seeing a benefit with UXA, someone
   with the exact same chip has reported a serious regression.

Q: How hard would it be to backport/SRU all of the upstream fixes for UXA?

A: UXA by design relies more extensively on the kernel, and thus a
   number of bugs require fixes to the kernel-side DRM.  Coordinating
   X/Kernel stable release updates is considerably more resource
   intensive than ordinary X updates.

Q: Would more testing feedback of UXA help?

A: Not at this time.  We have already made the determination about UXA
   with the 2.6.x driver for Jaunty so need no further testing feedback
   on that.  Instead, test upstream's git tree and provide feedback to
   them directly.

Q: When will UXA be turned on by default?

A: At this time our plans are to switch to UXA by default after Karmic
   opens for development.

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