Comment 151 for bug 1488719

Hi,

we recently got our new E7450 Notebooks from Dell and encountered the same Problems.
Main Problem - Displays flickering or turn to black at all.
We use 3 Displays 2x externeal via DP / HDMI 1920x1080 + E7450 build in with 1920x1080.

OS is Ubuntu 14.04LTS with Kernel 4.2.0-30-generic.
I also tested few hours ago the latest Kernel 4.5.0-040500rc7-generic but after a few minutes one Display started to flicker again.

The dmesg messag "[drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!" occurs in 4.2 but not in 4.5.

There is another dmesg message in 4.5 that seems to be related to the i915 driver:

[Di Mär 8 17:51:44 2016] pci_bus 0000:02: Allocating resources
[Di Mär 8 17:51:44 2016] pci_bus 0000:03: Allocating resources
[Di Mär 8 17:51:44 2016] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment
[Di Mär 8 17:51:44 2016] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment
.
.
.
[Di Mär 8 17:53:14 2016] WARNING: CPU: 0 PID: 1278 at /home/kernel/COD/linux/drivers/gpu/drm/i915/intel_uncore.c:599 hsw_unclaimed_reg_debug+0x69/0x90 [i915]()
[Di Mär 8 17:53:14 2016] Unclaimed register detected after reading register 0x223a0

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

Hardware:
E7450
Graphics:
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 i have a:
03:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 840M]
but its not in use.

If you need more Information ...
Thank you in advance
Thomas