No signal from X Server after turn TV off then back on

[Mark A. Taff]

Hardware:
  Intel NUC NUC5i5RYK, Intel HD Graphics 6000, core i5
  LG TV, model 47LA6200-UA

Bug is reproducible on demand.

I have the box connected to the TV via HDMI.

Steps to reproduce:
1) Turn on TV
2) Boot into Linux, log into KDE
3) Turn TV off, leave computer running
4) Turn TV back on
5) TV reports no signal for input

At state #5, cannot get the signal back by:
a) shaking mouse,
b) pressing keyboard keys
c) unplugging, then reconnecting, HDMI cable

At state #5:
  --login via ssh from remote computer works
  --top shows all processes running as typical for KDE
  --able to start x11vnc via ssh from remote machine, then connect to display :0 using KRDC as a client; KDE still works fine
  --I can get the signal back by killing X form a local tty, or remotely vis ssh, in which case X will restart and I will get the signal back until the next time I turn off the TV, though that requires me to relogin to KDE and start from scratch as the session isn't saved when you kill X that way.

Workaround (seems to work, at least for cases when TV is off for a few minutes):
  --Before shutting of TV, switch to tty1 (Ctrl+Alt+F1)
  --Shut off TV
  --Turn TV on when you next want to use it
  --tty1 will show up, switch to tty7 (vt7), and it works as expected.
  --on the prior step a console message is printed:
          [timestamp] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!

The same message also repeats upon HDMI cable disconnect/reconnect.

I'm currently using the latest Intel drivers from https://01.org/linuxgraphics but the issue also presents with default kubuntu drivers.

I suspect the issue has to do with the HDMI handshake not being renewed/restarted when the TV comes back on. Even when in state #5, the TV detects when the HDMI cable is unplugged ("No cable connected" vs "No signal from input").

Let me know if you need any additional information or if I can do anything to help with debugging.

Thanks!

--Mark

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xserver-xorg-core 2:1.17.2-1ubuntu9.1
ProcVersionSignature: Ubuntu 4.2.0-19.23-generic 4.2.6
Uname: Linux 4.2.0-19-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Wed Dec 2 16:20:43 2015
ExecutablePath: /usr/bin/Xorg
InstallationDate: Installed on 2015-09-04 (89 days ago)
InstallationMedia: Kubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
SourcePackage: xorg-server
UpgradeStatus: Upgraded to wily on 2015-12-01 (1 days ago)

[Mark A. Taff (q-maak-p)]

Also, this was happening in 15.04 as well, so it isn't likely to be caused by the upgrade to 15.10.

[Mark A. Taff (q-maak-p)]

The workaround works on time scales of a week, at a minimum, with multiple TV on/off events.

[penalvch (penalvch)]

Mark A. Taff, thank you for reporting this and helping make Ubuntu better.

Could you please run the following command once from a terminal as it will automatically gather and attach updated debug information to this report:
apport-collect -p xorg 1522174

Please ensure you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

When reporting xorg related bugs in the future, please do so via the above method. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]