[Intel-gfx] PROBLEM: displayport MST external monitors don't return from sleep mode

Jani Nikula jani.nikula at linux.intel.com
Thu Jan 14 01:20:19 PST 2016

On Thu, 14 Jan 2016, Derek Yerger <dy at drexel.edu> wrote:
> Kind Regards,
> Derek Yerger
> Computer Engineering
> 10171358 / djy24
> [1.] displayport MST external monitors don't return from sleep mode
> [2.] When displays go to sleep, upon return from sleep the two monitors 
> attached to a belkin mini displayport to 2x HDMI, do not return from 
> sleep. This results in part of the desktop being inaccessible, until the 
> external displays are unplugged, and then plugged back in.
> Sometimes, Xorg will also back down to one monitor. The data 
> accompanying this report is for an instance where the power save mode 
> caused Xorg to drop to the primary monitor only.
> This is on a Dell XPS 13 (9333) using intel i915. There are two external 
> monitors connected by HDMI to a DP-MST adapter which connects to the 
> single mini-displayport. A single-HDMI-to-mini-displayport adapter works 
> as expected (coming out of power save).
> The bug can be reproduced by either letting the screen power save 
> timeout elapse, or by running "xset dpms force off"

Please report i915 bugs at the freedesktop.org bugzilla:

But before doing so, please check if your issue might be one of these
existing DP MST bugs: https://goo.gl/VERzzh


Jani Nikula, Intel Open Source Technology Center

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