Compiz by default ? -- In a word, NO

[Raymond Lillard]

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My view is as a user of Linux since the mid-90's, a
X-Window System user since the late 80's and a bit
of a curmudgeon.  I have built Linux and X from source
dozens of times.  Thanks to Ubuntu and Fedora I haven't
needed to do is so much of late.  For this, I am grateful.

The Gutsy release as I understand it is to be a LTS
(long term support) release.  I believe it should be
as polished as possible.  It should install cleanly
and do as many things as possible without tinkering.

I believe this because Gutsy will become the new standard
by which Linux on the desktop is judged.

These tasks must be rock solid:
* Normal office tasks (memo, spreadsheets, presentations)
* Internet (mail, web browsing, embedded Java, Flash video & audio)

These tasks are important and if done poorly will be
black eye for all Linux:
* Play multimedia (CD, DVD [1], streaming audio & video - most formats)

These things while nice to have, are not so important.  Those of
us who require them are much better able to hammer Linux/X into
submission than general office users or home users such as Grandma.
* Gaming ( accelerated video, 3D )
* Scientific applications (data presentation, modeling, etc.)

The first two categories do not depend on composted video
and Compriz must not interfere or degrade the experience
of users who mainly focus on those tasks.

For this reason, please do not put Compriz in a LTS release.

Release it in Gutsy+1, +2, ..., so when the next LTS
comes around, it will be ready.

Regards all,
Ray

[1] Yes, I know about dvdcss and the surrounding legal issues.
    That horse has already left the barn and is not relevant
    to my point about Compriz.




Michael Vogt wrote:
> Dear Friends,
> 
> 
> one of the goals for this cycle was to enable compiz by default for
> all systems where this is feasible. We added a detection from Tribe-2
> on to see if the system is able to run compiz and turn it on then.
> This detection works well and we are happy with the results.
> 
> We still need to discuss if we should enable compiz by default for the
> final release or not. This discussion was started yesterday by
> Matthew Garrett at the techboard meeting and it was decided that this
> needs to be discussed in a wider forum. 
> 
> The remaining issues with enabling compiz by default are that there
> are the following regressions compared to a non-composited system:
> 
> Video playback - basic Xv playback should work on all video drivers we
> support [1] but there is no composited video playback. That means, that
> all effects will just give a black window for the video player. Moving
> the window around results in a black window too until the window is
> settled, then the playing comes back.
> 
> Windowed 3d applications - currently the 3d hardware renders directly
> into the framebuffer. This means that no transformation effects are
> possible [2], but it also means that no damage events are generated
> when a window is moved around. This results in artifacts on the screen
> where the 3d application was. You can try this on a compiz system by
> runing glxgrears (intel, ati) and move it around on the screen or move
> another window over it. Work is being done in this area, but it will
> not be ready for gutsy.
> 
> Performance regression on windowed 3d applications - some video
> drivers drop significantly in 3d performance when compiz is
> running. For fullscreen apps this can be worked around with a compiz
> setting, but not for windowed 3d applications.
> 
> General performance regressions - people with older hardware will see
> a slow system when compiz is enabled because of the additional
> requirements it imposes on the hardware (especially on systems with
> CPU < 1Ghz, older GPUs).
> 
> 
> The above regressions make composite-by-default something we really
> need to discuss. The question is if we should tradeoff the usability
> improvments and blink improvements for the above regressions. 
> 
> I think the video playback will just look like a cosmetic issue
> (unprofessional at worst), but if users run into the windowed 3d
> rendering artifacts that will look like we ship something that is
> broken.
> 
> What we need to do in any case is to raise awareness to the users
> about this feature. If we decide to enable it by default we should
> popup something that explains that certain things may not work quite
> well. If we decide that we should not enable it, we should have a
> check that tests if it is likely that the system is able to run compiz
> and if so, popup a notification that tell them what to do to enable
> desktop-effects. The effects tab in the apperance capplet should also
> get some additional text that explains that desktop effects may cause
> issues with windowed 3d applications. 
> 
> 
> Thanks, 
>  Michael
> 
> 
> [1] see https://wiki.ubuntu.com/CompizTeam "Status of Xv video"
>     section
> [2] http://hoegsberg.blogspot.com/2007/08/redirected-direct-rendering.html
> 


- --
Ray Lillard
rlillard at sonic.net




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