Lockscreen multiscreen behavior

[Martin Gräßlin]

Am 2015-06-17 14:39, schrieb David Kahles:
> On 06/17/2015 05:30 AM, Martin Gräßlin wrote:
>> Am 2015-06-16 16:58, schrieb David Kahles:
>>> Hello,
>>> I want to hear some opinions about the multiscreen behavior of the 
>>> lockscreen.
>>> 
>>> Currently the lockscreen is displayed on all connected monitors. I
>>> would prefer if the
>>> lockscreen is displayed only on the primary monitor, as it's done at
>>> the loginscreen,
>>> because there is no need for multiple instances.
>>> I think this also matches the behavior of other operating
>>> systems/desktop environments.
>>> 
>>> What do you think?
>> 
>> When we redid the lockscreen to be in QML with the lock always shown 
>> we did it that way on purpose. The main problem is that we don't know 
>> which screen the user is expecting it to be on. Even more we don't 
>> know whether the primary screen is actually the user's primary screen. 
>> We cannot expect users to configure it as they use it.
>> 
>> Easy example: notebook, external screen connected, internal screen is 
>> obviously the primary screen as it's a notebook. Now user closes the 
>> lid, screen stays configured to be on and locks the screen: at that 
>> point user has a broken system because lock screen is not shown any 
>> more. User might even try to hard turn off the system at that point, 
>> because user doesn't even think of the idea the closed notebook screen 
>> could have the locker.
>> 
>> So overall: if we want to be sure that users always can lock in again, 
>> we need to show on all screens.
> That makes sense, it could save much trouble.
> Out of curiosity: why should the monitor in the closed lid be
> configured to stay on? The only reason that
> comes to my mind is, when the lid-closed sensor is broken.

in an ideal world: not needed. In the world we live in (X11) it might be 
needed. Consider the case that I plug in an external TV to my notebook 
to watch a movie and close the lid. If it would disable the output, I 
would get about 1-2 min of freezes, becuase XRandR/Intel is freezing. In 
addition Plasma would start to shuffle everything around, KWin would 
shuffle everything around for things I don't need. I'm happy with all my 
open windows to stay on the notebook screen even if they are not visible 
to me as in that usecase the only thing that matters is the vlc on the 
big screen.

Cheers
Martin