Hi guys,

At work I've installed Debian Testing + KDE on my Imac . Everything went well until I tried to use another screen in complement. Actually, when I uncheck Unify outputs in the Display and Monitor administration section, KDE totaly freezes.

Do you have an idea of what's going on ? What should I look at ?

By the way, I'm using the nouveau driver.

Thanks

This is quite probably a driver problem. Are you using desktop effects? If so, can you try disabling them and then performing the change to de-unify the screens to see if that has any effect?

It's a little better when effects are disabled.
But still, this lags a lot and the CPU load goes up to 99% for 30-45 seconds (process kworker). After this, my screen is recognized. But the freeze comes back randomly.

Unfortunately it seems that the Nouveau driver only partially supports your graphics card - in particular it's multihead capabilities.
There is not much further I can suggest - other than lowering the resolutions you are using on both cards to try to reduce the stress on the driver/graphics card, which might avoid the freeze.

Just wanted to share that everything works perfectly with the proprietary Nvidia drivers. Thanks bcooksley for your help