Multiple problems with multiple monitors

Basil Mohamed Gohar basilgohar at
Tue Nov 4 17:30:56 UTC 2014


On 2014-10-13 10:23 AM, Basil Mohamed Gohar wrote: 

> I've searched for bugs related to the specific problems I've been having, and I've not been able to find anything that describes what I'm seeing. 
> I have an HP EliteBook 840 that also comes with an UltraDock, to which I've plugged-in two external monitors and I use in conjunction with the built-in laptop display. 
> Issue #1: I use LUKS to encrypt my disk, and when I first start up the computer, after choosing the kernel to boot into in GRUB, the GUI prompt for the LUKS passphrase shows-up on the middle monitor, not the laptop's built-in display. I don't mind this when I have multiple monitors plugged-in, but when I boot-up without the external monitors, such as when I'm unplugged from the UltraDock, I now get NO GUI prompt for the LUKS passphrase. I can enter it, and I can see a text prompt if I hit ESC. I suspect its attempting to display on the now phantom, unplugged monitor. Note, it was never plugged-in during this cycle. The problem is, I don't even know what's instructing LUKS or the GUI prompt to display on any monitor, so I don't know where to go to debug this. 
> Issue #2: When I undock my laptop while logged-in, Gnome Shell just crashes. When I redock after the laptop has been started when unconnected, one of the two external monitors start-up (the one connected by VGA), but not the one connected by a DisplayPort connection. And, recently (but not when I first started using this laptop with the dock, which was about a month ago), now when I start-up with the laptop docked and both external monitors connected, both external monitors will be active, but the built-in display will show nothing. Gnome Shell reports the built-in display is active, but will not display anything unless I deactivate it and reactivate it via the settings "Displays" utility. 
> Issue #3: The monitor connected via DisplayPort display significant tearing and delay on the upper-right half of the screen in the form of a triangle taking-up half of the screen. Reading about displayport and tearing issues, I guess the idea that these were resolved in the past. I don't know if this is the same or something different. 
> I don't mean to use devel as a bug reporting venue, but I think these issues are either related or I just don't know how to address them to make significant progress to fixing them. Any guidance is more than welcome. Thanks! 
> -- 
> Libre Video

So, a recent update which included a kernel update fixed issue #2, and I
was really happy. Then, another update this week, which included
multiple systemd updates, restored/rebroke issue #2 above (the
docking/undocking) issue. 

Libre Video
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