Hi,

Doesn't looks like a duplicate of bug 1626935 to me!

The flickering in my case happens:
- only when something light happens in somewhere on the external screen (like 
entering a single character in a terminal window). When nothing happens on 
screen, or when using graphics-heavier apps (like a web browser), the screen 
doesn't flicker
- the flickering is not similar to a triple buffering issue neither is related 
to the nautilus wallpaper -- it looks like a DisplayPort reset (ie, as if you 
disconnect/reconnect the monitor), with a 2-3s complete blackout of the monitor
- this is specific to the modesetting driver. The xserver-xorg-video-intel 
driver is fine.


** This bug is no longer a duplicate of bug 1626935
   [yakkety] desktop is black and/or flickering after plugging in a second 
monitor

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https://bugs.launchpad.net/bugs/1636486

Title:
  External screen flickers (esp. in terminals) with xorg modesetting
  driver on Intel Broadwell

Status in xorg-server package in Ubuntu:
  New

Bug description:
  Hi,

  I'm using a Dell XPS 13 (9343 // i7-5600U broadwell, 3200x1800 panel)
  laptop, directly attached to an external Dell P2715Q 4K (3840x2160
  @60Hz) via DP.

  The 4K external screen is flickering when doing light activity --
  easily reproduced when using an X terminal.

  Steps to reproduce:
  - open side by side Firefox (or Chrome) + a terminal and/or a gvim window on 
the external 4K screen
  - do some light web browsing
  - give focus to the X terminal or gvim
    // at this point, display is still perfectly steady
  - press a key to enter a single character
    // as soon as the key is pressed, external screen goes black for a few 
seconds. Laptop screen is not affected.
  - Wait for the screen to come back, then continue typing
    // screen generally stays ON, but sometimes continues to flicker a few 
times in next minute.

  This happens almost every time I switch to the terminal window and
  start typing.

  OS specs:
  - Ubuntu 16.10 running Unity, modesetting Xorg driver
  - kernel 4.8.0. Issue is still present with 4.9.0rc1.

  The intel driver (cp /usr/share/doc/xserver-xorg-video-intel/xorg.conf
  /etc/X11) doesn't exhibit this issue.

  
  Also reported upstream: https://bugs.freedesktop.org/show_bug.cgi?id=97264

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