haswell i915 black screen regression with DVI; VGA ok?

[Dan Kegel]

After a recent update (early Nov 2016), my 16.04 system (an HP Pavillion 500-321, i.e. a generic i5-4570 system with integrated graphics) started showing a black screen on boot (after the grub menu finished).
A fresh 16.10 live USB image also has the same problem on this system (but not on an nvidia system),
as does a fresh 16.10 install.
A fresh 16.04 install does NOT have the problem; the problem
can be reproduced on this system by doing a fresh 16.04 install followed by letting it update
automatically to the latest 16.04 packages.

After some experimentation, I discovered that after booting up into the black screen,
I could (usually?) rescue the session by pressing the computer's power button. This brought the
screen to life, showing Ubuntu's "reboot or power down?" dialog. Cancelling that left
you with a working system. I also discovered
that if I booted first to text mode with
   sudo systemctl set-default multi-user.target
and then after logging in via text mode, switch to graphics with
   startx
or with
   sudo systemctl start graphical.target
the screen also was fine.

So, um, er, is it a race condition? Is graphical.target missing a wants? And what recent update could be introducing this problem?

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.1
ProcVersionSignature: Ubuntu 4.4.0-45.66-generic 4.4.21
Uname: Linux 4.4.0-45-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Sun Nov 6 14:00:22 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [8086:0412] (rev 06) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [103c:2af7]
InstallationDate: Installed on 2016-11-06 (0 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Hewlett-Packard 500-321
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-45-generic root=UUID=a3be56db-508b-49ea-9d57-7f8270d98e4e ro
SourcePackage: xserver-xorg-video-intel
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/27/2014
dmi.bios.vendor: AMI
dmi.bios.version: 80.18
dmi.board.name: 2AF7
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 1.04
dmi.chassis.asset.tag: MXX4320BPH
dmi.chassis.type: 3
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnAMI:bvr80.18:bd06/27/2014:svnHewlett-Packard:pn500-321:pvr1.00:rvnHewlett-Packard:rn2AF7:rvr1.04:cvnHewlett-Packard:ct3:cvr:
dmi.product.name: 500-321
dmi.product.version: 1.00
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.12.2+16.04.20160823-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.2
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.2
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Sun Nov 6 13:52:03 2016
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 9170
 vendor ACI
xserver.version: 2:1.18.3-1ubuntu2

[Dan Kegel (dank)]

Seems to have gotten worse with the next batch of updates (linux-image-4.4.0-47-generic:amd64); now it won't show a screen at all, even when booting to multiuser, after the kernel sets the
graphics mode. Works fine if I give nomodeset, but then I can't use accelerated graphics.

[Dan Kegel (dank)]

I booted with drm.debug=14 and looked at the output of dmesg. It had lines like
[ 0.717202] [drm:i915_dump_device_info] i915 device info: gen=7, pciid=0x0412 rev=0x06 flags=need_gfx_hws,is_haswell,has_fbc,has_hotplug,has_llc,has_ddi,has_fpga_dbg,
...
[ 0.938640] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:36:VGA-1] disconnected
[ 0.938641] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:39:HDMI-A-1]
[ 0.938642] [drm:intel_hdmi_detect] [CONNECTOR:39:HDMI-A-1]

which made me realize: the drm driver cares a lot about which video connector you plug
into. On a whim, I replaced the DVI video cable with a VGA one... and the problem went away!

So, that's a better workaround for me: just use a vga cable.

[Dan Kegel (dank)]

Not sure which package this should be against; since it might be DRM, maybe it should be against the linux kernel?