[Bug 94479] New: i915 external Displays flicker / turn black

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=94479

            Bug ID: 94479
           Summary: i915 external Displays flicker / turn black
           Product: DRI
           Version: XOrg git
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: thoehlig at benocs.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org
     i915 features: display/HDMI

Hi,
I recently got a new notebook and I have the problem, that the external
displays attached via HDMI / DP (via e-dock) flicker or turn black and loose
signal.
Normaly after around 3 seconds both external Displays turn back to normal.
(Only the external displays)
We have several notebooks sharing this problem, all with the same hardware and
always the same setup:

3 Displays 2x external via DP / HDMI 1920x1080 + E7450 build in with 1920x1080.

With the default ubuntu kernel 4.2.0.30-generic I got the dmesg message:
[drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!

I tested a newer Kernel (see below), the error messages dissapeared but the
display problems are still present.

There is a corresponding bug report @ ubuntu launchpad
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1488719 and
here https://bugs.freedesktop.org/show_bug.cgi?id=92084.
There are 2 more launchpad user who encountered exactly the same behaviour.


uname -m x86_64
uname -r 4.5.0-040500rc7-generic
Distro: Ubuntu 14.04
Machine: E7450 Dell Latitude
Display connector: 2x HDMI / DP via eport + internal Display
lspci: 
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated
Graphics (rev 09) (prog-if 00 [VGA controller])
 Subsystem: Dell Device 062e
 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping-
SERR- FastB2B- DisINTx+
 Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
 Latency: 0
 Interrupt: pin A routed to IRQ 51
 Region 0: Memory at f5000000 (64-bit, non-prefetchable) [size=16M]
 Region 2: Memory at d0000000 (64-bit, prefetchable) [size=256M]
 Region 4: I/O ports at f000 [size=64]
 Expansion ROM at <unassigned> [disabled]
 Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
  Address: fee00018 Data: 0000
 Capabilities: [d0] Power Management version 2
  Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
 Capabilities: [a4] PCI Advanced Features
  AFCap: TP+ FLR+
  AFCtrl: FLR-
  AFStatus: TP-
 Kernel driver in use: i915

in addition we have a:
03:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 840M]
but its not in use.

modinfo i915
filename:
/lib/modules/4.5.0-040500rc7-generic/kernel/drivers/gpu/drm/i915/i915.ko
license: GPL and additional rights
description: Intel Graphics
author: Intel Corporation
author: Tungsten Graphics, Inc.
firmware: i915/bxt_dmc_ver1.bin
firmware: i915/skl_dmc_ver1.bin
firmware: i915/skl_guc_ver4.bin
srcversion: A8C37B25F49F03AE77E49D0

cat /sys/class/drm/card0/error 
no error state collected

dmesg with drm.debug=0x1e log_buf_len=1M as attachment.
The dmesg output ends after screens returned to normal. I didnt change the
screen, tabbed to terminal and cat dmesg > file.

xrandr --verbose as attachment too.

If you need more informations, please let me know.
Thank you in advance

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