[SKL-U] System hangs when switching video out to the next mode

[Vanessa Chang]

After update to test kernel 3.19.0-32.37+bpo1, system will hang with blackscreen while switching to the next mode with HDMI video out.
* The function works fine with -28 kernel.
* SKL-H doesn't find this issue

Test configs:
Intel SKL-U graphics: Dell Inspiron 13-7359

Kernel version: 3.19.0-32.37+bpo1
---
ApportVersion: 2.14.1-0ubuntu3.12
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: u 2108 F.... pulseaudio
CRDA:
 country TW:
  (2402 - 2472 @ 40), (3, 27)
  (5270 - 5330 @ 40), (3, 17), DFS
  (5735 - 5815 @ 40), (3, 30)
CurrentDesktop: Unity
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-kittyhawk2-trusty-amd64-20150907-1
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=UUID=61acef2b-8b38-40a2-a2a1-1f8346dbfa80
InstallationDate: Installed on 2015-11-06 (2 days ago)
InstallationMedia: Ubuntu 14.04 "Trusty" - Failed to find casper uuid.conf in 'binary/casper/initrd.img-3.19.0-28-generic.old-dkms' LIVE Binary 20150907-22:18
MachineType: Dell Inc. Inspiron 13-7359
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-32-generic root=UUID=fc10fc31-8426-4eb5-8157-35d5d5c70335 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.19.0-32.37+bpo1-generic 3.19.8-ckt7
RelatedPackageVersions:
 linux-restricted-modules-3.19.0-32-generic N/A
 linux-backports-modules-3.19.0-32-generic N/A
 linux-firmware 1.127.15
Tags: trusty
Uname: Linux 3.19.0-32-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 09/08/2015
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 01.02.00
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr01.02.00:bd09/08/2015:svnDellInc.:pnInspiron13-7359:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct9:cvr:
dmi.product.name: Inspiron 13-7359
dmi.sys.vendor: Dell Inc.

[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Vanessa Chang (vanessa-chang)]

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[Brad Figg (brad-figg)]

This change was made by a bot.

[Timo Aaltonen (tjaalton)]

So this should happen with the wily kernel too, keeping it open until verified.

[Timo Aaltonen (tjaalton)]

err, "unless proven otherwise"

[Timo Aaltonen (tjaalton)]

Could you test mainline 4.3 and if it doesn't work, latest drm-intel-next from

http://kernel.ubuntu.com/~kernel-ppa/mainline/

[Vanessa Chang (vanessa-chang)]

Tested below kernels which still fails with the same symptom:

1) v4.3/ 4.3.0-040300 #201511020949
2) v4.3 unstable/ 4.3.0-040300 #201511020846
3) drm-intel-next/ 4.3.0-977 #201510290447
4) drm-intel-nightly/ 4.3.0-044 #201511102100
5) bpo2.1/ 3.19.0-32.37+bpo2.1
6) 3.19.0.34-39+bpo1
7) 3.19.0.33-38

[Timo Aaltonen (tjaalton)]

So the offending commit got added in -29 to the vivid kernel, and upstream is just as affected. The recent patch to add support for DP MST didn't fix this (-32.37+bpo2.1 and -34.39+bpo1 had it).

Will be bisected (should be easy) and sent upstream.

[Timo Aaltonen (tjaalton)]

been a while.. could you check newer drm-intel-next mainlines to see if this is now fixed upstream

[Timo Aaltonen (tjaalton)]

closing the bug, it should work fine in xenial