Comment 4 for bug 1581302

This has worked to re-display my screen power is removed and then
re-applied to the monitor, I'm doing further testing to see if it also
fixes the issue with lockscreen blanking and sleeping.

On Thu, May 19, 2016 at 8:25 AM, Jan <email address hidden> wrote:
> Please try the patch mentioned here:
> https://bugs.launchpad.net/bugs/1308105
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1581302
>
> Title:
> Monitor remains blanked with Intel Graphics
>
> Status in lightdm package in Ubuntu:
> Confirmed
>
> Bug description:
> Running on a NUC5i7RYH, latest BIOS. ASUS Monitor connected via Display Port or HDMI
> Running Xubuntu 16.04 - latest all current patches
>
> Sometimes the monitor remains blanked even when the session has
> reactivated.
>
> I have been able to reproduce this problem by letting the monitor
> remain in the 'blanked' state for > 60 minutes, or powering off the
> monitor. When the monitor is powered back on and the session is woken
> up with mouse or keyboard input, it does wake up but the monitor
> remains blanked.
>
> I was able to prove to myself the session was awake by leaving it with
> terminal opened to full screen with VIM running on an NFS mounted file
> system. I could type and save at the black monitor screen and see that
> the file got updates from a different system. So the session is "live"
> but the computer has forgotten to re-establish the DisplayPort link.
>
> An error appears in the lightdm logs about setting a CRTC, if you
> activate an alternate terminal (say with CTL-ALT-F1) and try `xrandr
> --output DP1 --auto` it also registers that CRTC error. HOWEVER, if
> you ssh in from a different machine, tell bash to export DISPLAY=:0
> (set $DISPLAY to ':0') and then type 'xrandr --output DP1 --auto' the
> screen turns on again! This also happens on a Gigabyte BRIX system
> (same NUC reference design but in that case a core i3 rather than a
> Core i7).
>
> To reproduce, turn off the monitor, wait an hour, and turn it on
> again.
>
> You can also kill HUP the lightdm process and that will restart a new
> session (but open windows in the previous session are lost).
>
> So interesting questions, why does typing xrandr "locally" give you
> the error but running it from an ssh session work?
>
> Since xrandr and restarting the session can both "fix" the problem,
> the driver seems to know how to turn the display on if told correctly.
>
> How can I find out where the code is getting the CRTC error?
>
> ProblemType: Bug
> DistroRelease: Ubuntu 16.04
> Package: lightdm 1.18.1-0ubuntu1
> ProcVersionSignature: Ubuntu 4.4.0-22.39-generic 4.4.8
> Uname: Linux 4.4.0-22-generic x86_64
> ApportVersion: 2.20.1-0ubuntu2
> Architecture: amd64
> CurrentDesktop: XFCE
> Date: Thu May 12 20:33:01 2016
> InstallationDate: Installed on 2016-05-08 (4 days ago)
> InstallationMedia: Xubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
> LightdmDisplayLog: (II) AIGLX: Suspending AIGLX clients for VT switch
> LightdmLog:
> [+80180.09s] DEBUG: Seat seat0 changes active session to
> [+80189.53s] DEBUG: Seat seat0 changes active session to 64
> [+80222.67s] DEBUG: Seat seat0 changes active session to c4
> [+80222.67s] DEBUG: Session c4 is already active
> SourcePackage: lightdm
> UpgradeStatus: No upgrade log present (probably fresh install)
>
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