flickering in fullscreen on Linux with Intel gpu and SNA

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MrAnderson
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flickering in fullscreen on Linux with Intel gpu and SNA

Post by MrAnderson »

If you are running warzone on Linux, using Intel graphics with SNA (Sandy Bridge New Acceleration) enabled, and you experience flickering objects when in fullscreen mode, then you probably have some sort of compositing activated. This is a known bug (https://bugs.freedesktop.org/show_bug.cgi?id=58005). However, a proper fix will take a while as the problem lies in the DRI2 protocol.

Easy workarounds:
- deactivate SNA, use UXA instead (you will probably loose some performance)
- deactivate compositing ("desktop effects")
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aubergine
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Re: flickering in fullscreen on Linux with Intel gpu and SNA

Post by aubergine »

Thanks for sharing this info!

I've started a wiki page in the hope of compiling a list of common graphics issues in one place: https://warzone.atlassian.net/wiki/disp ... ics+Issues

Do you have any screenies or instructions on how to deactivate those things (or is that something all linux users, even n00bs, will know how to do)? If so, could you post them here and I'll update the wiki page (probably just with a link to this topic).
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stiv
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Re: flickering in fullscreen on Linux with Intel gpu and SNA

Post by stiv »

Generally speaking, compositing window managers (Aero, compiz, kde4) and transparent desktop effects do not get along well with OpenGL. It's like cats and dogs, only with pixels.
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NoQ
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Re: flickering in fullscreen on Linux with Intel gpu and SNA

Post by NoQ »

stiv wrote:Generally speaking, compositing window managers (Aero, compiz, kde4) and transparent desktop effects do not get along well with OpenGL. It's like cats and dogs, only with pixels.
Curiously enough, my new amd-based netbook is fairly stable: with proprietary ati drivers, i have most kwin4 effects turned on (including blur) and have absolutely no problems with watching videos and playing games, not even a slightest performance degrade. I'm surprised myself >_<
MrAnderson
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Re: flickering in fullscreen on Linux with Intel gpu and SNA

Post by MrAnderson »

Sorry for taking so long. I thought I had email notifications on replies activated for this thread. Turns out I had not.
aubergine wrote:I've started a wiki page in the hope of compiling a list of common graphics issues in one place: https://warzone.atlassian.net/wiki/disp ... ics+Issues
Great.
Do you have any screenies or instructions on how to deactivate those things (or is that something all linux users, even n00bs, will know how to do)? If so, could you post them here and I'll update the wiki page (probably just with a link to this topic).
I guess most Linux users who play warzone2100, even noobs, will find out how to deactivate compositing in one or another way without much pain (most will just turn off desktop effects completely). The exact way to accomplish this depends on the desktop environment you are using. For example in KDE4, you can find the settings in >systemsettings >desktop effects.

Deactivating SNA is a bit harder. As of this writing, most people do not use SNA (instead of UXA), as they would have to turn it on manually (for X this can be done in the global xorg.conf which is usually found at /etc/X11/xorg.conf). And if they have activated it manually, they probably know how to deactivate it again.

However, some distributions have started making SNA the default choice (Ubuntu 12.10?). So, if you encounter severe problems using SNA and you did not manually activate it, you need to manually edit your X configuration. This is dangerous and you will need root permissions for this. If you do not have root access (like with su or sudo) or you just do not want to edit configuration files, you might want to try a different solution (like turning off desktop effects, playing in windowed mode or writing a bug report in the bug tracker of your distribution and waiting for a fix).

If you still want to edit your xorg.conf, you should know that you can prevent X from starting up if you break the configuration file (and if you play around e. g. with modeline settings it is even possible to damage your hardware).

Editing xorg.conf can not be described in few lines (actually, often this file needs to be created first). Therefore, I recommend searching the web for a guide. If you have succeeded in creating a working xorg.conf (X -configure should be ok in most times) and you created a Device section, selecting the intel driver, all you need to do is setting the option

Code: Select all

	Option	"AccelMethod"	"uxa"
in that section.