After upgrading to 4.2.0.30 Elantech touchpad not detected

[Thomas Zell]

see bug #1549354 for a detailed description

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-4.2.0-34-generic 4.2.0-34.39~14.04.1
ProcVersionSignature: Ubuntu 4.2.0-34.39~14.04.1-generic 4.2.8-ckt4
Uname: Linux 4.2.0-34-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CurrentDesktop: Unity
Date: Sat Mar 19 23:04:54 2016
InstallationDate: Installed on 2016-01-06 (73 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
SourcePackage: linux-lts-wily
UpgradeStatus: No upgrade log present (probably fresh install)
---
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: magda 1854 F.... pulseaudio
CurrentDesktop: Unity
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=/dev/mapper/ubuntu--vg-swap_1
InstallationDate: Installed on 2016-01-06 (73 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 8087:0a2a Intel Corp.
 Bus 001 Device 002: ID 0bda:57cc Realtek Semiconductor Corp.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Acer TravelMate B116-M
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.2.0-34-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash
ProcVersionSignature: Ubuntu 4.2.0-34.39~14.04.1-generic 4.2.8-ckt4
RelatedPackageVersions:
 linux-restricted-modules-4.2.0-34-generic N/A
 linux-backports-modules-4.2.0-34-generic N/A
 linux-firmware 1.127.20
Tags: trusty
Uname: Linux 4.2.0-34-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 11/13/2015
dmi.bios.vendor: Insyde Corp.
dmi.bios.version: V1.20
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: BA10_BA
dmi.board.vendor: Acer
dmi.board.version: V1.20
dmi.chassis.type: 10
dmi.chassis.vendor: Chassis Manufacturer
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsydeCorp.:bvrV1.20:bd11/13/2015:svnAcer:pnTravelMateB116-M:pvrV1.20:rvnAcer:rnBA10_BA:rvrV1.20:cvnChassisManufacturer:ct10:cvrChassisVersion:
dmi.product.name: TravelMate B116-M
dmi.product.version: V1.20
dmi.sys.vendor: Acer

[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[Thomas Zell (t-zell)]

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[penalvch (penalvch)]

Thomas Zell, the next step is to fully reverse commit bisect from kernel 4.2 to 4.5 in order to identify the last bad commit, followed immediately by the first good one. Once this good commit has been identified, it may be reviewed for backporting. Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection#How_do_I_reverse_bisect_the_upstream_kernel.3F ?

Please note, finding adjacent kernel versions is not fully commit bisecting.

After the fix commit (not kernel version) has been identified, then please mark this report Status Confirmed.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Thomas Zell (t-zell)]

I was not able to identify a non-working mainline kernel. Therefore, I do not know what to bisect.

Both mainline 4.2.0-040200 and 4.2.4-040204 which are the mainline builds available for wily closest to 4.2.0-30 work.

I suspect, the bug is not present in the mainline kernel at all.

[penalvch (penalvch)]

Thomas Zell, then it would appear a downstream patch is the cause of this issue. Hence, let this be marked Triaged for now.