Compiz by default ?

[Patrice Vetsel]

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You should also know that when you have compiz enabled, vino can't work.
So there is no possibility to help a user by taking control of the
desktop/mouse/keyboard by internet, until it disable compiz.
Bug #77442
https://bugs.launchpad.net/ubuntu/+source/vino/+bug/77442

Regards


Michael Vogt a écrit :
> 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
> 

- --
Patrice Vetsel <ubuntu at kagou.fr>
Aka/Alias Kagou
https://launchpad.net/people/vetsel-patrice
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